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Aquarium Advice Apprentice
Nov 30, 2023
So a lot, actually most of this, fish tank water parameters is over my head to be honest. My family just got 5 tetras & 4 guppies in a new 10 gallon tank (and one betta in a 5 gallon tank but he’s doing well). I’m sad that in less than 2wks we’ve already lost two AND after a partial water change, about 25-30% (assuming I’m even doing this correctly), one of my guppies is starting to isolate himself and hang near the top. The first two died 4 days ago. They were eating and active and within 24hrs both started to act lethargic, lose their color, and isolate themselves near a top corner of tank. I’m hoping he is just stressed from the water change today and will be okay in the morning, but now I’m worried something was going on before my water change. Can someone give me advice according to my current water parameters. After testing the water about 2hrs after the partial water change (I have tap and so conditioned the water with API stress coat drops), here are the results:
GH= ~150-200ppm KH= 180ppm pH= 7.8-8.0
Are these too high for my guppies and tetras? What I’ve been reading is that they’re a little high, but idk if it’s high enough to try and adjust and risk the pH fluctuating too much. I want to do whatever I can to keep our fishies happy and healthy and I’m worried I’ve done something wrong today. This one guppie was fine and ate a good meal before the water change. Also, today was the first time I did a water change after having the new tank in a little less than two weeks (followed my local pet stores recommendation). Maybe he’s just stressed out right now, but I’m worried. Another thing to add, but may be insignificant to the cute situation, but just in case it’s useful… all four guppies are/were males. Everything I’ve read says this is a no-no bc male guppies can be aggressive with one another, which I never saw any aggressive behavior when I was around, but the pet store said it was perfectly fine. ��*♀️ I appreciate any advice! Thank you all
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You havent mentioned cycling the aquarium.

Are you aware of the nitrogen cycle and how to cycle a tank?

Do you know your water parameters beyond the pH, KH and pH? The most important parameters to know are ammonia, nitrite, and nitrate as these relate to the nitrogen cycle and cycling your tank.

Im going presume you didnt cycle the tanks. In which case your water change of once in two weeks isnt enough. Until you are able to provide ammonia, nitrite and nitrate you should be changing half the water every day. The reason your fish are dying is because the aquariums arent cycled which allows waste to build up very quickly and the water becomes toxic. Until your tank cycles you need to help things out by frequently changing water.

Tetras are naturally from soft, acidic water. Guppies are from harder, higher pH water. Fish are adaptable, and can acclimate to parameters outside of their ideal range as long as you arent too far out. Your water is better for the guppies than the tetras.

Your 5g tank is ideal for the betta, but a 10g tank is probably too small for tetras. Tetras are social fish and prefer to kept in larger groups. Mosts tetras should be kept in groups of 6 or more, preferably 10 or more. They are also active swimmers, so a 10g aquarium isnt really big enough to support a group of tetras. For this reason, along with the hardness/ pH of the water i would stick to the guppies in the 10g. A group of 8 to 10 male guppies will be good. They can get aggressive while establishing a pecking order, but if you have a nice group the aggression tends to get spread out rather than targetted at one individual, if there are no females to fight over, aggression is usually limited, and no females means no babies. Guppies are prolific breeders and your tank would quickly get overtaken with a mix of M/F fish.

For now, dont get any more fish. Let's find out what your water parameters are and get the tanks cycled. Do those daily water changes until we know where your cycle is at.
The nitrogen cycle is the natural processes that go on in your tank that convert ammonia into less harmful substances.

Ammonia gets into your tank through various pathways. Fish waste, decaying uneaten food, and dead, decaying plants are common ammonia sources in an aquarium. Its also possible your tap water is an ammonia source. Chloramine is a common water treatment and when treated with most water conditioners the bond in the chloramine breaks and releases ammonia into the water.

Ammonia can be toxic to fish, depending on how much there is, and what the pH and temperature of your tank water is.

The first stage of the nitrogen cycle is the removal of ammonia. If you have real plants in your tank some of this ammonia will be absorbed as part of their natural growth. Generally though ammonia is consumed by denitrifying bacteria that lives mostly on your filter media. These bacteria consume the ammonia and produce nitrite. Unfortunately nitrite is pretty much as toxic to fish as ammonia.

The second stage of the nitrogen cycle is the removal of nitrite. A different denitrifying bacteria will consume the nitrite and produce nitrate. Nitrate is much less harmful than ammonia and nitrite, and for most aquariums the nitrogen cycle ends there. Excess nitrate is removed through your regular water changes.

A further stage of the nitrogen cycle can also happen, but its difficult to remove all the nitrate from a typical freshwater aquarium. Plants will absorb some nitrate in a similar manner to how it absorbs ammonia to grow. There are also nitrifying bacteria that consumes nitrate and gives off nitrogen gas which will simply offgas from your aquarium. This nitrifying bacteria is difficult to grow in freshwater aquarium.

“Cycling” a tank is the process you go through to grow denitrifying bacteria in your aquarium to consume ammonia and nitrite. You are said to be “cycled” when you have enough bacteria to consume all the ammonia and nitrite that your tank produces and turns all of it into nitrate. If you test the water of a cycled tank you should see 0 ammonia and nitrite and some nitrate.
Thank you so much for all of the information. Very informative and eye opening for a beginner like me. You are correct, I did not cycle the water. I was gullible enough to believe drops would allow me to “instantly & safely add fish”. After a long trip to the er with my 16mo today, I was surprised to come home this evening to find all my fish still alive. The tetras actually seem to be doing “okay”. They ate for me. The two guppies are still not acting right. One little guy is moving its tail as if it’s hyperventilating, while trying to hide. Neither guppie ate for me :( I was able to read up on Nitrogen cycle when my daughter would nap on and off and I’m guessing after the water change AND the tank not being properly cycled, I’ve stressed everyone out. I wish I would have checked the water parameters before doing a water change to compare the before and after. Right now my nitrate, nitrite, and ammonia look to be at 0. Here is a pic of the levels from today (early this morning. I did not make it home in time to check it this evening before my son went to bed like I hoped). My nitrate and nitrite levels should be a little different each day indicating the nitrogen cycle is in play correct? The water is starting to look just a little cloudy, and I read where that’s a normal process in the whole nitrogen cycling process, would you agree to this? ( I do apologize if I’m using the words incorrectly. I’m still trying to completely understand it all ). I also read a little about RO too. Should I use any RO water or distilled water or maybe add some peat moss or java fern to help lower the GH some for the tetras? Im a little scared to do anything at all for fear more change in the water will push them completely overboard, if I haven’t already. I’ve read different things on the internet as far as how often to do water changes.. you still advice to do them daily for a little while? I really wish the pet store had advised against the tetras for our 10gallon tank, and the fact that they prefer softer water conditions compared to the guppies. I hate that they won’t be as happy as they could be. Should have done my research before getting fish. I had no clue what all was involved in the fish tank world. Thank you again for all your help. It is very much appreciated.

I can’t get the picture to upload for me for whatever reason. The readings were : 0 on the ammonia, nitrite, and nitrate. PH was 7.8-8.0. KH was a little over 140ppm and the GH was ~180ppm.
Hope your little one is well.

On the face of it your water parameters are safe. What test kit are you using? Liquid tests are more accurate than test strips. Strips just arent accurate and they could say everything is fine when they arent.

Lets assume the test is good. You want to test the water every day. Take your ammonia and nitrite test and add them together. If they are more than 0.5ppm combined then change some water. If you go a week without needing a water change, then change half the water anyway.

As for lowering the pH and hardness, the only effective way to do this is to mix your tap water with soft water like RO or distilled. Adding peat moss, driftwood, or catapa leafs will release tannins into the water which will also make the water softer and lower pH and hardness a little bit, but will also make your water brown, which you might not like the look of.

Its up to you really. The tetras would be better in softer, more acidic water, but they also need a bigger tank. You also arent having problems with your tetras health, its the guppies. If it were me i wouldnt go messing about with water chemistry beyond cycling the tank, and longer term decide if tetras are what you want to keep and get a bigger tank if you do. Guppies will be fine in the 10g.

Do you know what type of tetra you got?

If you hit the "go advanced" button you can add photod by then hitting the "manage attachments" button. Or upload your photo to a site like imgur and just post a link.

When you figure out how to post a photo can you add a photo of a sick guppy? And one of the tetras if you dont know what kind of tetra it is.
Newbie- tank

Thank you, we just got our first set of stitches. Good to go now lol. I will go buy a liquid test kit today and double check my readings. The test strips I have are made by API. Is that a decent brand? We have neon tetras. All fish seem to be doing a little better this morning, but the guppies are hiding from me if they notice me watching. Before they were social with me. If they don’t realize I’m here they’re swimming around lol. Thank again for your help! I’ll repost those readings with the new test kit as soon as my husband gets back with them :)
Oh and I am used this for those “cycle drops”.


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Another question I have, so when my tanks show that I have nitrates, then I can consider the water as cycled? Also on feeding, I’ve read to feed them what they will eat in 2-3min (which is a lot bc they will eat a good amount to me, well the guppies did, not so much now) but I’ve also read not to feed too much. What do you suggest? Thanks again for putting up with my beginner questions.
Forgot to add ?*♀️ the liquid test kits showed zero ammonia, nitrites, and nitrates and the ph is 7.8-8.0. Water is still on the harder side. I don’t understand how there is zero ammonia if I haven’t done things as I should have and I’ve got 8 fish.
Good to hear fresh water is improving things.

API is a good brand. Their liquid test kit is the go to. But test strips of any brand arent very reliable. The API Freshwater master test kit is a good one to go for.

Im a big fan of fluval equipment, but their consumables not so much. Despite what it says on the bottle of fluval cycle it wont cycle a tank. At best it might speed things up a little, from several months to several weeks, but more often it wont do anything. Ive used that product and seen no difference compared to the time i would expect it to take without it.
Okay thanks!! Do you still recommend daily water changes?
Lets assume the test is good. You want to test the water every day. Take your ammonia and nitrite test and add them together. If they are more than 0.5ppm combined then change some water. If you go a week without needing a water change, then change half the water anyway.

Be guided by your water test.
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