Troubleshooting a whole lot of death for a newbie!

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Claireh703

Aquarium Advice Apprentice
Joined
Jan 13, 2021
Messages
13
Hi!

I'm relatively new to all this as I was given an aquarium in May 2020 when a friend was concerned that her fish wouldn't survive a cross-country move. Unfortunately, the fish haven't had the best survival rate staying with me either. I'd love to have any advice on how to improve that survival rate before we invest in more fish.

We have a 20 US gallon tank with gravel substrate, a few live plants and some ornaments. The temperature remains at about 79 degrees. Whenever we test the levels of the water (sporadically!), they are all ok. We have never treated the tap water because it's well water but I'm now curious as to whether it's also chlorinated. We have a light that is turned on for about 12 hours a day.

We use an Aqueon QuietFlow 30 filter - we upgraded in size from the one I inherited because we had regular algae bloom and my husband thought the tank capacity was far larger than it is. (I measured it to write this post and pointed out his mistake!) We put the filter on the one side at the back so that there was a difference in water flow for the fish. The fish tend to hang out on the opposite side for the majority of time but will also swim confidently around the filter end too. We did have a few small fancy guppies that struggled with the flow in their first few days but were fine after that. We still have the original filter (Aqueon Tech 10-20) so can switch back if needed now we've realised our (my husband's!) mistake!

We use a vacuum to pick up poop and excess food without taking any water out once or twice a week. (We were doing it every other day when struggling with algae bloom but have reduced it and it hasn't made an impact on the levels when tested). We change 10% of the water once a week and change 50% once a month.

We feed them TetraMin 3-in-1 every other day... most feeds, just the flakes and I'll add some granules for the bottom feeders. Once a week, I'll use the baby shrimp instead of flakes but have to grind them up as they ignore them whole. I've tried lettuce and blanched spinach but none of the fish will eat it.

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I got the aquarium (in May) with 2 plants, 2 corys, a guppy and another fish I can't remember what it was that we'll call "the white fish". I don't know how long my friend had had these fish. I had a lot of algae bloom (tank was in the window because I didn't know better) to begin with but got over that and all 4 survived. In June, we added 2 more plants and 2 honey gouramis. In August, the white fish died suddenly - no observed illness or strange behaviour. We replaced it with another fish that I also don't know what type that we'll call "the yellow fish" and bought 2 plecos. One of the plecos died a few weeks later.

These fish withstood algae blooms, cooler temps than recommended, overfeeding and bad tank hygeine as I was still learning / experimenting. We gave the tank and all non-living things a good clean (without cycling it... I didn't know that was a thing then) when we moved in early October. (All the above info about the tank, feeding, temp, etc became consistent from then on.) In November, the yellow fish died and we replaced it with a molly.

In late December, we were away for 2 weeks. A few days before we left, one of the gouramis and the guppy began to slow down and be near the top but showed no visible symptoms. We believe the person looking after the fish in our absence didn't vacuum to debris out and we came home to a dirty tank, algae bloom and the gourami and guppy "missing" - the caretaker hadn't noticed or removed them. When vacuuming the tank, we found what we believe to be some very decomposed "bits". The plants are alive but have been in decline since.

In early January, the remaining gourami appeared to have fungus or something on it's anus but was eating and behaving fine and it passed after a week or so. We bought two guppies - one didn't survive 24 hours. I had the water tested at the pet store and they said it was all good and they replaced the guppy and I bought a mystery snail. The replacement guppy died within 24 hours. The snail was incredibly lively and entertaining (who knew?!) for a few weeks and then suddenly died. The gourami got more and more pale over the last 3 weeks but it's behaviour was good until one day this week and then died the next day. Today, the molly looks to have a little fungus(?) on its head but I'm not sure if I'm just being paranoid.

So now we have the original 2 corys, a pleco and a molly that I'm not sure if I should be worried about.

I've really enjoyed having fish (which was a surprise to me!) and I want more but I want to make sure we are doing everything correctly so that they stop dying. All advice welcome! Once we've got a healthy set-up, I'd also like to know how many fish we can have in this tank.

Many thanks in advance!!
 
The molly died last night. I'd put in some Lifeguard All-in-one yesterday but it was too late.

I know I wrote a lot but any advice or suggestions is much appreciated! I really want to keep an aquarium but am ready to give up rather than keep letting fish die.
 
What are you water parameters? Is your tank fully cycled?
 
What are you water parameters? Is your tank fully cycled?

We only have the test strips so they're really vague:
GH: Between 0 & 100
NO3: Between 10 & 25
NO2: 0
Cl2: 0
KH: 80
pH: 7.2

How would I know if it's still cycled? Because there are 0 nitrites and nitrates are present? We inherited it set up when I didn't know anything about cycling (I still know little!) so the presumption is that it was cycled. However, when we moved in October, we had a pretty consistent algae bloom so took the opportunity to clean everything, changed the filter and probably changed more than 50% of the water so could have gone back a stage.

We have also been changing the filter cartridge monthly and not leaving in the old media because we didn't know better. Is it right to leave the cartridge in unless the filter slows and then, when we do put a new one, keep the old one in for 4 weeks? And between changes, rinse it if its gunky in tank water?

Would you recommend getting a master testing kit? And do you think I need to cycle it (with fish)?

I'm also going to ask if our well water is treated in any way to see if we should be conditioning the water.
 
What's the ammonia level? That's an important factor. Yes, get a master kit - the liquid tests are far more accurate than test strips. And cut the lights down to 6-8 hours a day. Don't add any medication unless you know exactly what is happening, not as preventative.
Finally, if you are on well water, it is not chlorinated. If it was, the fish would die immediately. Never heard of well water being chlorinated.
Read about cycling a tank here https://www.thesprucepets.com/speed-up-aquarium-cycle-1380707
 
What's the ammonia level? That's an important factor. Yes, get a master kit - the liquid tests are far more accurate than test strips. And cut the lights down to 6-8 hours a day. Don't add any medication unless you know exactly what is happening, not as preventative.
Finally, if you are on well water, it is not chlorinated. If it was, the fish would die immediately. Never heard of well water being chlorinated.
Read about cycling a tank here https://www.thesprucepets.com/speed-up-aquarium-cycle-1380707

The strips don’t test for ammonia. I’ll pick up a master kit tomorrow and work out the level. Thanks for your help!
 
What's the ammonia level? That's an important factor. Yes, get a master kit - the liquid tests are far more accurate than test strips. And cut the lights down to 6-8 hours a day. Don't add any medication unless you know exactly what is happening, not as preventative.
Finally, if you are on well water, it is not chlorinated. If it was, the fish would die immediately. Never heard of well water being chlorinated.
Read about cycling a tank here https://www.thesprucepets.com/speed-up-aquarium-cycle-1380707

Ok, got a master kit. The parameters are:

pH 8.2
Ammonia 0.50ppm
Nitrite 0
Nitrate 20ppm

So, if the tank was fully cycled, the ammonia would be 0 and this might be why we're struggling?

What about the pH? Is that too high? Whats the best way to lower it?
 
Your tank shouldn't have ammonia, aren't you using mangrove wood? Your pH is quite high, at least you have to reduce it to 7.5, the mangrove will help you with that. I suggest you add liquid bacteria, what biological filtration are you using?
 
Your tank shouldn't have ammonia, aren't you using mangrove wood? Your pH is quite high, at least you have to reduce it to 7.5, the mangrove will help you with that. I suggest you add liquid bacteria, what biological filtration are you using?

Remember that I'm a newbie!

I've never heard of mangrove wood... can you explain what it does?

I thought the biological filtration was the nitrogen cycle?

Is the liquid bacteria needed in addition to cycling the tank again?
 
The mangrove will help you stabilize an ideal pH, when I had problems with high pH I added mangrove wood and also looked for a water source whose pH was managed between 7-7.5, and problem solved. I had my pH at 8.4 and some fish seemed fine but my wild angels couldn't stand it and passed away, so all I did was change the water supplier I was using, and with partial water changes my pH was set to 7.2, and it has remained there ever since; Get one or two mangrove woods to fit your tank size and that will help.
Bacteria are housed in porous elements (biological filtration), they can be ceramic rings or marine pure bio spheres (for example) and this helps you with the nitrogen cycle. I add liquid bacteria to each water change, only in the amount of water that I am going to replace.
 
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