Newbie needs serious help with his aquarium.

[matata]

A little backstory. I am an accidental aquarium hobbyist. About 2 months ago, I got a very small aquarium (2-3 gallon) as a gift, and he also stuffed it with 7 fish! (I know!). I didn't know (moderator edit) about aquariums or fish, but the person who gave it to me, assured me its very easy and he has good experience. I knew right away that it seemed too small for those fish, but he told me that its not, as a matter of fact he was thinking about giving me 4 more fish. After doing a little bit of research I quickly found out that the aquarium was barely big enough to hold one fish. Anyways, as expected two fishes died within 48 hours.

I didn't have money handy to invest on a bigger tank or support system, or even knew what I needed to do. I kept changing 50% water. and gave them a little food once a day. The rest survived but they got spots on their body.

Fast-forward today, I finally forced myself to invest some money to help the fishies out. I am in south-east asia (bangladesh), though I am sure there are some knowledgeable fish-tank expert here in this country, but I don't know any of them. Even the store employees doesn't seem to know what they are talking about.

Yesterday, I bought a fish tank. They couldn't tell me how much it could hold, but after using an online calculator (Tank Volume Calculator) I figured out that it can hold about 17.5 gallon or about 66 litres (Length: 24inch, Width: 12 inch, height 14 inch) I filled it up to 4/5th of its capacity for now (at the store they told me to fill it up 50% in the beginning, not sure why). I got a submersible filter, those oxygen bubble thingies, food, medicine, salt. I got these mostly from the store employees recommendation, except for the filter - which I got it on my own choice. I also got couple of more fish, the store guy told me I could put about 40 fishes in this tank, I was skeptical, and should have used my better judgement before getting more fishes.

Now that the backstory is out of the way. I have some specific newbie questions. I did some online research, and I could learn from trial an error and kill some more fishies on the way. But I am hoping you guys can help me speed up the learning curve.

- First thing first, need help identify the fishies. They told me the name, but I forgot which is which. Also they used local name for the fish, not sure I could remember them anyway. There is this beautiful fishy, they told me is called "Fighter Fish", I looked up online and they are also known as "betta". Another fish, a big black one, which only sticks to the glass with its mouth, making sucking motion, I was told it sucks out algae buildup, doesn't seem to eat regular fish food, I couldn't take its picture because it always hiding behind the filter. Right now I have 1 betta/fighter-fish, 1 algae eating one, 2 medium white, 2 golden color, 1 grey color, 2 flat black ones, 2 golden mini-me. The white and big golden ones are from the old tank and they have spots on them. Altogether 11 fishies, can you help me identify them? fishies - Imgur

- Next these are the medicine they gave me. How often, or if I should use them, at all? medi - Imgur

- Regarding the salt, I have read online that unless there is specific illness, there is no need to put salt. I did put a little bit of salt initially, but I am thinking about skipping it from now on. http://i.imgur.com/JW7mg5th.jpg

- I am feeding them this. Thoughts? http://i.imgur.com/yvFbOoTh.jpg

- I got this submergible filter (High Quality ALEAS Aquarium Tank Submersible Filter Practical Keep Water Clean | eBay) Looks like a ****** chinese knockoff, but it seems to be doing the job. The store owner told me that I need to run it only 4-5 hours a day and it should clean water about 20%. Online research tells me, I need to keep it running 24/7 and it does more that filter out water, it somehow also helps the good bacteria to grow. The type that keeps healthy balance of the water. Also if I have the filter running, do I also need the oxygen/bubble thingie? Because the filter seems to provide lots of "aeration" and bubble and the bubble/oxygen thing it quite loud.

- How often, if I need to change the water? 50-20%?

- Can I add more (small) fish to my current setup?

- Any other general tips?

Thanks for taking the time to read through this wall of text and helping me with my newbie questions.

 

[Fishfur]

It is very good you are trying to do the right thing. It is too bad your friend gave you a gift with such poor information and put you in the position you are in now. Don't buy any more fish 'til you get the ones you have sorted out and healthy.

But, oh my, you really should have done the research first.. but you know that now, I don't need to tell you. Did you learn about the nitrogen cycle ? Filters must run 24/7, and must have the media inside rinsed or squeezed out, in tank water only, before they get so dirty they clog up. Once weekly or bimonthly, depending how dirty they get.

You have fish that have very different cultural needs and should not be in the same tank. Betta fish, used to be known as Siamese Fighting Fish, often attack other fish, especially if it is male. If it has long flowing fins, it's a male. So if it starts flaring its fins at other fish or attacking other fish, it needs to be alone in that first tank you got, which is enough for it by itself.

There is a TON of information on Bettas online. Not all good, sadly, but read a bunch of them. They do best in tanks that are not smaller than 2.5 gallons, and better in larger ones. No matter how many sites say a little bowl is ok, it is NOT ok for any fish to live in a small bowl or container. But they do not need a filter. Instead you just do 50% water changes every 3 days or so. They do well on their own, and often do poorly with other fish. Keep the tank bottom bare and clean, but if you can put in some java moss, the Betta will like that. It will also like catappa tree leaves, that have fallen and dried up, in the tank. Catappa leaf, we call it Indian Almond here, is also good for infections generally, as it has antibacterial properties naturally. A leaf or two can be left in a tank 'til they are just skeletons, then replace them.

You also appear to have a small Angel fish, [ the dark one with the flat body], it would like Almond leaves too. Also an orange platy, and I think there are two goldfish, one orange, one near white. And I think I saw a red finned shark. dark body, reddish fins ? They need very large tanks, they get quite large, and it will soon outgrow this one.

Goldfish are cold water fishes. They eat a LOT. Very messy, very dirty, so you have to clean the tank and filter more often. They also grow fast and will, too soon, be too large for the new tank. Or they may become stunted by the small tank size and then not grow properly.

The Angel fish will eventually become fairly large, up to six inches tall from upper fin tip to lower fin tip is possible. Generally reasonably peaceful, but sometimes show aggression to other fish. Prefer softer, more acidic, warmer water than the other fish you have, but can adapt to most water conditions.

The platy, [ smaller orange fish at top of water in pic] is a good community fish that gets along with most fish that are not so large they'll eat it, and they are live bearing. If yours is female and has been bred, you may get baby fish quite unexpectedly. She will eat them, and so will all the other fish. Be prepared for that if you can't remove them to another tank or breeding net enclosure. If she was in a tank with males, as is likely, chances are good she's pregnant. They reproduce very easily if they have access to mates. Many fish will eat other fish, if they will fit into their mouths. So be aware of that.

Last, that 'sucker' fish. It is probably a Plec.. plecostomus. If it is a Plec, it may need driftwood to chew on. Many of them require wood to be healthy. Many Plecs can become quite large. You need to find out what it is for sure. Also check for salt tolerance, I have a feeling they are one of the species that cannot tolerate salt, but I am not sure of that. I know other catfish can't take salt, so check that.

You need to feed that one algae tablets or sinking algae pellets, unless your tank has a lot of algae in it for them to consume, or it may starve. It takes them longer to eat and they usually eat at night, so if there's left over food next day, siphon it out and feed less next time, until it is all gone the next day. Best fed once a day in the evening. You can also give them small slices of blanched root vegetable, like cucumber or zucchini squash, or watermelon rind, that sort of thing. Remove uneaten veggies the next day so they won't rot and ruin the water. It might even like blanched spinach or some similar leaf vegetable.

For the other fish, feed only as much as they will completely consume in two or three minutes, twice a day and no more. More food just fouls up the water. Flakes are fine, or small floating pellets. What you have is ok for most of them, except the Plec.

Bettas are often fed pellets, but a balanced flake is ok. Just don't give more than he can eat in a couple of minutes. They will often come to the tank front to be fed once they learn the routine.

If possible, I would try to find another home for the gold fish. Don't get me wrong, I like them. They can be very personable and friendly as fish go. They just won't do well for long where you have them. They'd do well in a pond, or maybe you could trade them at the store for another platy fish or two ?

The Angel and Platy should be ok together, but the Angel and platy may pester one another if they are the only ones in the tank, especially once the Angel grows larger. Having a couple of other small fish would be better than just one.. two or three platies, or a couple of sword fish, would be nice if you can rehome the gold fish.

Incidentally, the old rule of thumb for how many fish you can have is one inch of fish [body length, not fins ] per gallon of water. For goldfish it's less than that, for fish that mature at two inches or less, it can be a bit more. Bottom feeders like the Plec, if that's what it is, are often not counted in this way, but they are actually quite dirty fish, so should be counted.

Read up on the nitrogen cycle. And if that filter has carbon in it, and you are going to use medication, remove the carbon. If you have it in the filter while you medicate, it will remove the meds before they have a chance to work. Carbon is used to remove colour, odour or medication from water, and is not needed otherwise. But the medication will only work if it is the right one for the illness. So first you must be at least somewhat sure of what those spots are.

The spots on the fish, which I can't see well enough in the pics, may be a few things. A common fish illness that shows up with spots is called Ich, or Ick.. and can be treated using salt and raising the temperature of the water. It is a parasite that will kill if not treated. Treat for several days past the time you see the last spot. The spots start out looking like grains of salt, but can get much larger if the parasites are not killed off.

Salt will also help cure fungal problems, and if the spots are fungal, it may be they had wounds that now have fungus. Fungus usually looks sort of cottony, whitish, and will spread.

Because the goldfish need colder water, if their water is too warm they will be more prone to getting sick. While you don't always need a bubbler, or air stone, the warmer the water is, the less oxygen it contains. To treat Ick, you raise the temperature, so the air stone is needed to help improve the oxygen levels while the water is warmer. It can also help to improve gas exchange in general, which happens only at the water surface, so if the filter does not break the water surface when it returns water to the tank, I'd keep the air stone until you can drop the temperature. The splashing is what helps the gas exchange. If you can get the filter to splash water back into the tank, that helps too and you might do without the air stone.

The Betta fish will benefit from a small amount of salt in the water but the other fish do not need it and should have not have it unless they are sick and it is used to treat them. Then you do water changes to reduce and eventually remove the salt. A good pinch to 2.5 gallons is right for the Betta as part of his regular routine.

Read up on the nitrogen cycle, so you understand how the bacteria in the filter change the waste that fish produce from very toxic ammonia to slightly less toxic nitrite and then less toxic nitrate. Plants can help improve water and use up nitrate, but the gold fish will eat or destroy them. The other fish will enjoy having some plants.

Water changes should be done regularly, usually about a quarter of the tank water is changed about once a week, but it depends on how many fish, tank size, etc. New water should be the same temperature as the tank water is before it's added. You need to siphon up the poop off the tank bottom when you change the water too.

You should have a water test kit, that will test for pH, ammonia, nitrite, and nitrate at the very minimum. Without the tests it is very hard to find out what might be causing illness or if your water is ok for the fish you have.

I would have to look up how much salt you need to add to help with fungus or Ick, but you can do that too. Look up Ich, or Ick, it is spelled both ways. It is a parasite and can be treated but it takes some time and has to be done properly or it just keeps reproducing and the fish will die eventually as the Ick feed on them. Not table salt ! Aquarium salt, sea salt or even kosher salt, but not table salt, which has additives to make it pour better and not cake.

If the pictures of Ick are not a match for your fish spots, look up fungal infections. Both can be treated with salt, which is good medicine for most fish. But some species cannot take salt, and if that sucker fish is a Plec, that may be one species that can't take salt. There are hundreds if not thousands of pictures of the many, many species of plecostomus in the aquarium hobby online. Usually called Plecs by hobbyists, some stay relatively small, but some grow to be enormous fish that need enormous tanks. If you could trade him for some other fish, it's something to consider, as he may well outgrow that tank very fast. I used to keep the common Plec many, many years ago, in a thirty gallon tank. I'd buy one at two inches, traded it back at eight inches within the year for other fish and another Plec. They get to be huge. But not all of them do, there are a number that don't grow huge, but you need a species ID to know what size it will become. Check those pics.

Fungal problems are sometimes due to wounds, but can be poor water conditions or stress as well. The organisms that cause it are always in the tank water, waiting for an opportunity to take hold. So you see them called opportunistic infections as well, and bacterial issues are also like this, present always but don't cause trouble unless an opportunity arises, such as poor water, stressed fish or wounds.

You really need to find another place for the gold fish as soon as you can, or for the other fish, they can't stay together for any great length of time and remain healthy.

If your local water has chlorine or ammonia added to it at a water treatment plant, you must use a dechlorinating product to remove this before adding it to fish tanks. If you have well water, you should be ok, but if anything is added to sanitize the water, make sure it's treated before using it for fish. Fish are very sensitive to chlorine, chloramines, [ which are what you get when you combine chlorine and ammonia at the water plant ] free ammonia, nitrite and nitrate plus many other compounds. Water changes are one way to help remove some of the compounds that build up, but can't make up for not treating water or lack of filtration.

Btw, that filter looks very, very small. How much space is inside for filter media ? If you can, fill it with sponge or filter floss, or both, instead of whatever refill the manufacturer sells for it. Sponge is good biomedia, lasts a long, long time, floss also lasts well, both are easy to clean, just squeeze out well in tank water.

Hope that helps a bit, I wish you luck.

 

[Fishman007]

A little backstory. I am an accidental aquarium hobbyist. About 2 months ago, I got a very small aquarium (2-3 gallon) as a gift, and he also stuffed it with 7 fish! (I know!). I didn't know (moderator edit) about aquariums or fish, but the person who gave it to me, assured me its very easy and he has good experience. I knew right away that it seemed too small for those fish, but he told me that its not, as a matter of fact he was thinking about giving me 4 more fish. After doing a little bit of research I quickly found out that the aquarium was barely big enough to hold one fish. Anyways, as expected two fishes died within 48 hours.

I didn't have money handy to invest on a bigger tank or support system, or even knew what I needed to do. I kept changing 50% water. and gave them a little food once a day. The rest survived but they got spots on their body.

Fast-forward today, I finally forced myself to invest some money to help the fishies out. I am in south-east asia (bangladesh), though I am sure there are some knowledgeable fish-tank expert here in this country, but I don't know any of them. Even the store employees doesn't seem to know what they are talking about.

Yesterday, I bought a fish tank. They couldn't tell me how much it could hold, but after using an online calculator (Tank Volume Calculator) I figured out that it can hold about 17.5 gallon or about 66 litres (Length: 24inch, Width: 12 inch, height 14 inch) I filled it up to 4/5th of its capacity for now (at the store they told me to fill it up 50% in the beginning, not sure why). I got a submersible filter, those oxygen bubble thingies, food, medicine, salt. I got these mostly from the store employees recommendation, except for the filter - which I got it on my own choice. I also got couple of more fish, the store guy told me I could put about 40 fishes in this tank, I was skeptical, and should have used my better judgement before getting more fishes.

Now that the backstory is out of the way. I have some specific newbie questions. I did some online research, and I could learn from trial an error and kill some more fishies on the way. But I am hoping you guys can help me speed up the learning curve.

- First thing first, need help identify the fishies. They told me the name, but I forgot which is which. Also they used local name for the fish, not sure I could remember them anyway. There is this beautiful fishy, they told me is called "Fighter Fish", I looked up online and they are also known as "betta". Another fish, a big black one, which only sticks to the glass with its mouth, making sucking motion, I was told it sucks out algae buildup, doesn't seem to eat regular fish food, I couldn't take its picture because it always hiding behind the filter. Right now I have 1 betta/fighter-fish, 1 algae eating one, 2 medium white, 2 golden color, 1 grey color, 2 flat black ones, 2 golden mini-me. The white and big golden ones are from the old tank and they have spots on them. Altogether 11 fishies, can you help me identify them? fishies - Imgur

- Next these are the medicine they gave me. How often, or if I should use them, at all? medi - Imgur

- Regarding the salt, I have read online that unless there is specific illness, there is no need to put salt. I did put a little bit of salt initially, but I am thinking about skipping it from now on. http://i.imgur.com/JW7mg5th.jpg

- I am feeding them this. Thoughts? http://i.imgur.com/yvFbOoTh.jpg

- I got this submergible filter (High Quality ALEAS Aquarium Tank Submersible Filter Practical Keep Water Clean | eBay) Looks like a ****** chinese knockoff, but it seems to be doing the job. The store owner told me that I need to run it only 4-5 hours a day and it should clean water about 20%. Online research tells me, I need to keep it running 24/7 and it does more that filter out water, it somehow also helps the good bacteria to grow. The type that keeps healthy balance of the water. Also if I have the filter running, do I also need the oxygen/bubble thingie? Because the filter seems to provide lots of "aeration" and bubble and the bubble/oxygen thing it quite loud.

- How often, if I need to change the water? 50-20%?

- Can I add more (small) fish to my current setup?

- Any other general tips?

Thanks for taking the time to read through this wall of text and helping me with my newbie questions.

No offense but that was the poorest idea i have heard all week! You should have done some reasearch before doing that! You should go look up on google about how to keep fish and do some homework!!!!!!!!!! Good luck

 

[Frostshine]

Ouch. You have FOUR goldfish in that tank. WAYY too many for even the size you have, so I'm surprised they've lived this long. Those, the red tail shark, and possibly the pleco, will have to go. The goldfish are the big golden and white ones. The red tails can get quite big from what I've heard, and also aggressive. The pleco will most likely get HUGE, also, if it is a pleco. If you have algae problems, get a snail or two (but beware, they breed like crazy!). Watch the betta's behavior, in case of any aggression toward the other fish. The angels should be fine, just watch for aggression, again. If the two golden "mini-me"s (haha) are platies, as the one in the photo is, then they should be fine, but expect babies SOON! The one in your photo is ready to pop. If you want the fry to survive, move them to another tank, or get a breeder trap/net. Most, if not all, of the fish in there will eat platy fry.

Right now is NOT the time to add new fish ( (; ), but when that time comes (in more than a month, at least), some good beginners fish are

-Platies (like the ones you have)
They have many different color variations, as they are livebearers, and VERY easy to breed. Make sure the male-female ratio is at least 1-2, but 1-3 is even better. If you have ANY males in the tank with females, expect fry, and lots of them!

-Guppies
They are much like the platies, but slimmer, smaller, and with larger tails (mainly males). They sometimes don't do well with bettas because of their long tails being similar to a betta's. They are livebearers, and the same male-female ratio applies. I have guppies, and have had a lot of fun with them.

-Swordtails
They are, again livebearers, with the males sporting a "sword" at the bottom of their tails. They have many colors, again, but require more room than guppies and platies.

-Zebra Danios
They are egg layers, and have dark horizontal stripes on a golden background, giving them their name. They are very active, playful fish, but should be kept in schools of 4-5 at a minimum to prevent aggression and fin-nipping to other fish. They are fun and active fish, and very good starter fish.

-Neon Tetras
They are egglayers, too, but have a bright blue neon stripe running horizontally across their body, and a red one running halfway across. They are schooling fish, best kept at a minimum of 6. A very bright and friendly community fish, they can be kept with any tropical fish that won't harm or eat them.

These are just some of the beginner fish that I came across, I am sure there are many, many more. Most of my info was acquired via the Internet, so I could certainly be wrong. I'm fairly confident with my reply, though . I'm so sorry about your goldfish, shark, and pleco (possibly?). In order to keep them, though, you'd need an incredibly large tank. Find the exact species of the algae eater, though, and maybe his future WILL be with you . Either way, I am so glad that though you have been horribly mislead, you are willing to learn, and take advice. I hope I helped!

 

[matata]

@Fishman007 You are right, I should have done a little bit more research before jumping in, after the initial forced and unfortunate situation. But it can be overwhelming for a beginner when there are so many information and you don't even know where to start, or even what questions to ask. I mean how would I know about warm water/cold water fish, when I didn't even know such a concept exist. But I am learning fast and I am correcting some mistakes.

@Fishfur wow! thats an amazing collection of information and very specific to what I wanted to know. I can't thank you enough, I feel like I have made a jump from complete newbie to begin-intermediate level in the span of couple of hours. Its not that it took me couple of hours to read your comments, I read your comment and used the new knowledge to research for few hours. And I am a more knowledgeable/better person because of this. I am not done yet, I will be doing more research and try to make the best aquarium I can within my limitations.

@Frostshine thanks to you too. Like @Fishfun, you have also helped me understand new things and confirm some of the things I have recently learned. Really appreciate it.

Now to some of the more specific questions and concerns and plan of action:

- Confirmed all fish names as I googled their names provided by you. Thanks.
I have 4 gold fish (2 of them are white goldfish), I have 2 mollie, 1 betta, 2 Angelfish, 1 Pleco, 1 rainbow shark. Total 11 fish.

- I will giving away the four goldfish today. Talked to store owner and he said he will take it back for free.

- The pleco I have looks like this. I will keep it for now, I will looking for birch wood and pleco specific food.

- All other fish will stay as it is for now.

- For about one month I will NOT be adding any more fish.

- From now on I will be only adding small tropical fish.

- I will be changing water 50% once a week.

- I will be looking into small aquarium ornaments/caves/stones for fishes to hide.

- Filter will stay on 24/7. I will squeeze the sponge out inside the aquarium once a month.

- I won't be adding any salt, unless absolutely needed, during spots or fungus outbreak. Currently it doesn't look there is any spots or fungi problem, the red marks on goldfish, I confused them with spots, but they are probably blood clots, happened during their stay in the small aquarium.

- I will de-chlorine water before adding to the tank.

- I will be looking into test kit for chemical level, but I have my doubts if I can get them where I live. But I will keep an eye out.

- The filter seems to be doing its job. The last 2 days the water was kinda foggy (new tank), today it looks very very clean. The filter can pump/clean 200 liter an hour. Since my tank is 60L when full, but only 4/5th filled up, I think this filter should be enough.

Thanks guys for your very helpful tips. I hope to be more active in this forums and hopefully learn many new things in the process.

Cheers!

 

[Tank Girl]

The "filter" you have is nothing more than a powerhead with a pre-filter on it. It will NOT do the job!!

 

[matata]

The "filter" you have is nothing more than a powerhead with a pre-filter on it. It will NOT do the job!!

Can you tell me what's the difference between this "Filter" and a "Proper Filter"?

Today I opened the filter to look inside the "Sponge like thing" and it was quite a bit covered with grime like stuff.

 

[Fishman007]

@Fishman007 You are right, I should have done a little bit more research before jumping in, after the initial forced and unfortunate situation. But it can be overwhelming for a beginner when there are so many information and you don't even know where to start, or even what questions to ask. I mean how would I know about warm water/cold water fish, when I didn't even know such a concept exist. But I am learning fast and I am correcting some mistakes.

@Fishfur wow! thats an amazing collection of information and very specific to what I wanted to know. I can't thank you enough, I feel like I have made a jump from complete newbie to begin-intermediate level in the span of couple of hours. Its not that it took me couple of hours to read your comments, I read your comment and used the new knowledge to research for few hours. And I am a more knowledgeable/better person because of this. I am not done yet, I will be doing more research and try to make the best aquarium I can within my limitations.

@Frostshine thanks to you too. Like @Fishfun, you have also helped me understand new things and confirm some of the things I have recently learned. Really appreciate it.

Now to some of the more specific questions and concerns and plan of action:

- Confirmed all fish names as I googled their names provided by you. Thanks.
I have 4 gold fish (2 of them are white goldfish), I have 2 mollie, 1 betta, 2 Angelfish, 1 Pleco, 1 rainbow shark. Total 11 fish.

- I will giving away the four goldfish today. Talked to store owner and he said he will take it back for free.

- The pleco I have looks like this. I will keep it for now, I will looking for birch wood and pleco specific food.

- All other fish will stay as it is for now.

- For about one month I will NOT be adding any more fish.

- From now on I will be only adding small tropical fish.

- I will be changing water 50% once a week.

- I will be looking into small aquarium ornaments/caves/stones for fishes to hide.

- Filter will stay on 24/7. I will squeeze the sponge out inside the aquarium once a month.

- I won't be adding any salt, unless absolutely needed, during spots or fungus outbreak. Currently it doesn't look there is any spots or fungi problem, the red marks on goldfish, I confused them with spots, but they are probably blood clots, happened during their stay in the small aquarium.

- I will de-chlorine water before adding to the tank.

- I will be looking into test kit for chemical level, but I have my doubts if I can get them where I live. But I will keep an eye out.

- The filter seems to be doing its job. The last 2 days the water was kinda foggy (new tank), today it looks very very clean. The filter can pump/clean 200 liter an hour. Since my tank is 60L when full, but only 4/5th filled up, I think this filter should be enough.

Thanks guys for your very helpful tips. I hope to be more active in this forums and hopefully learn many new things in the process.

Cheers!

Your tank is to small for angels, the pleco, the rainbow shark and you should get rid of the betta.

You can ether keep the mollies in 75ºf water or the goldfish in 65°f water its your choice but make you decision quick because in low temps mollies are super prone to a horrible parisite called ich.

 

[Fishman007]

Can you tell me what's the difference between this "Filter" and a "Proper Filter"?

Today I opened the filter to look inside the "Sponge like thing" and it was quite a bit covered with grime like stuff.

Your filiter is a mechanical filter which means it will take some of the waste out of the water but you need aswell biological filtration which grows bacteria and keeps down on nitrites and ammonia which is deadly to your fish go to the store and get a aqueon quietflow 20 from petsmart there pretty cheap at 20$ and read the instructions!

 

[Tank Girl]

I believe he said he's in Bangladesh. Probably doesn't have a PetSmart there. Look online for "aquarium power filters". Good brand names are Marineland, Whisper, Aquaclear.

The pre-filter is mechanical filtration only. It's purpose is to keep the powerhead cleaner. The powerhead's purpose is to move water, not filter it. Powerheads are just small water pumps, not filters.

 

[Rivercats]

Just to give you an idea of the various types of aquarium filters here are some pictures to look at.... pictures of aquarium filters - Google Search.
You will have to see what is available in your country.

The small sponge prefilter on powerhead you have will clog up almost on a daily basis which is why you need to try to find a proper filter.

I understand that you want to keep all the fish except the goldfish, which you are returning but you need to reseach those and any fish you intend to keep in the future to see how big their adult size is and what size tank they need to be in. The Angelfish, the Pleco, and the Redtail Shark are all going to quickly outgrow your current tank.

Here is a good article to read about cycling your tank with fish in it, which is what is occurring in your tank now.... I just learned about cycling but I already have fish. What now?! - Aquarium Advice.

Since this is a new tank it will go through an ammonia and nitrite cycle which will be very harmful to your fish. During the next 5 to 6 weeks you need to do a 25% WC every day to keep these toxic levels down as low as possible. Don't think about adding any fish for at least 2 months and honestly you shouldn't add any fish as you are already overstocked.

After about 6 weeks you can go down to doing one 50% WC weekly.

Right now the most important thing is to do every day 25% WC while your tank is cycling. Also feed your fish very lightly.

 

[matata]

Thanks guys, I will look into proper filters around here. There are some big Aquarium stores over here, but they are quite a bit far away from where I live, I will check them out probably next weekend.

As for Pleco, Angelfish and Redtail shark. I will wait a bit till they grow bigger. So I have some time in my hand. I think removing 4 goldfish today made things much much better for the rest of the fish.

I will also start doing daily 25% WC as advised.

Knowing what I know now, it boggles my mind how so many fish were able to survive in that small 3 gallon tank I used to have. For 2 month and without a filter too. The only thing I did was water change every other day. But the fish did suffer (which I know now), with blood-clots and didn't look very healthy.

Thanks again.