🐠 October TOTM Starts Now! 🐠
FishForums.net Tank of the Month!
Click here to enter!


New Member
Sep 20, 2018
Reaction score
my red tailed shark has been acting strange for a couple days, two of my other fish(clown loaches) died and they were acting the same way. I don’t have a clue what’s wrong, I tested my water nitrate reads about 30, nitritereads .5-1.0, water hardness is very soft, chlorine is 0, total alkalinity is about 80, the ph is between 7.8 and 8.4.... he swims he kind of sideways and he isn’t eating just hiding and lays on his side all of the time. My other freshwater tank uses the same water and none of those fish have an issue.. I use aquarium rocks as substrateand I’ve already treated the water for diseases.. can anyone help?


  • D6FEF891-276F-4AB8-A4B4-ABB04184B422.jpeg
    879.6 KB · Views: 248
Hi and welcome to the forum :)

How long has the tank been set up for?
What is the ammonia level in the tank?

If the water is cloudy like in the picture, I am guessing there is an ammonia reading that is poisoning the fish. Nitrite will also kill fish.

You need to reduce feeding to once every second day and do a 75% water change and gravel clean the substrate each day until you have 0 ammonia and 0 nitrite.
Last edited:
In addition to the questions Colin raises...

How long has this tank been running with fish? How was it cycled initially?

What additives/treatments are you using, and why? This is very important as all substances added to the water in the tank will naturally get inside the fish, and usually this adds more stress so things can get worse.

The nitrite is a very serious issue, but the answers to all our questions will help us.
The tank has been running for about 4 months. I tested the ammonia today and it read zero, the nitrite levels were higher than I thought so today I put in API stress + zyme. I clean it regularly, I use a water conditioner and aquarium salt. He seems to be doing better today, swimming around, feeding off the glass but he won’t eat the flake food I give him.
Although I use and recommend highly some API products, StressZyme is not one of them. I personally see no benefit to this product, and I do think it may be detrimental. It will not likely have any impact on nitrite (or ammonia) issues.

Salt. This can help nitrite issues. However, salt should never be used in an aquarium with freshwater fish species (with a very few exceptions) long-term such as a sort of "tonic" because it does harm to fish. It can be very beneficial as a treatment for some problems (ich, for one) but this is as a treatment for a specific issue. I don't know if you have been using salt all along, but if yes, that may be part if not the issue with the clown loaches dying and now the RTS. Loaches absolutely cannot tolerate salt continuously. But as I said, if you see nitrite above zero, this can help, but it should not be continued and hopefully the nitrite will resolve itself.

Water changes are essential here; significant volume, meaning 70-75% of the tank volume, daily if nitrite continues above zero, but otherwise I would do them alternate days for a week. [Note that Colin suggested much the same.] As a general rule, whenever I see something out of the ordinary, I do a major water change; it is interesting that sometimes that is almost all one needs, depending. Water changes are without doubt the most effective and beneficial task whether regularly or as here for issues.

Which conditioner? Not likely to be a problem, though there are a couple that are not the best because they contain additives that can be detrimental. But with ammonia or nitrite, a conditioner that also detoxifies these can be helpful until they no longer show in tests. But aside from that, I would use the simplest conditioner, as all you really need is a dechlorinator (for chlorine and/or chloramine). API's Tap Water Conditioner is what I have been using for a few years now, and highly recommend.

Most reactions