What's Wrong With My Tetra?

Welcome to the forum 

If there's finrot, then I would definitely recommend eSHa 2000 or Waterlife Myxazin. [Other medications for finrot do exist and may be fine instead, but I wouldn't recommend API Melafix in this situation as it's very weak and doesn't have the key ingredients you need (it's simply tea-tree oil).]

Whether you treat them in the main tank or in a hospital tank depends on whether you have one of these (plus filter and heater) and other tank occupants - best not to subject healthy tank occupants to unnecessary medication and therefore stress, and also best not to subject shrimp or snails to copper-based medication. Make sure that you remove any carbon from the filter - it will prevent the medication from working properly.

Thanks for the water quality results - that's good that you're keeping water at optimum levels, as that will be crucial to aiding recuperation, so keep up the good work.

Edited to add: Have now seen the video - yes, those fish definitely need medication. Some of them even look as though their spines are curved/bent/arched, so possibly not in good health either. How many fish do you have in the tank altogether?

Hi @terra firma  and welcome to the forum 

I have used eSHa 2000 previously, and always have some in the cupboard for emergencies.

With multiple occupants in a tank it can sometimes be close-to-impossible to catch poorly fish to isolate/treat them. Unfortunately, sometimes you do just have to treat the whole tank.

Please keep us updated on your situation.

Start with esha 2000 and don’t mix the two medications, from the video I can see this is a severe case and that you may also have to prepare yourself for the worst (just want to be upfront with you on this). Recommend you do some research into humane methods to bring things to a swift conclusion if this becomes required.

Re catching the fish if you want to give this another go (though don’t stress the already poorly fish out too much, try to lift the net up from underneath the fish. 

Esha 2000 is ok with your corys (some meds aren’t) which is good news.

Out of interest, what are the ingredients in Waterlife Myxazin? Is there an accompanying leaflet listing these?

I was away for the weekend. I've come back and the sickest fish has gone. It died . I combed the tank but can't find it. Looks like it was too sick for the medication.

I don't want other fish to eat it and get disease. Hopefully the snails will eat it. I will continue to medicate the rest of the tetras.

Sorry to hear that a fish has passed. I hope that the others respond well to the medication.

4th day medicating the Myxazin.

Amazing, the 9 neon tetras tentativily explored the other end of the tank for the first time in months. They seem more alert and are feeding better. The mouth growths on the three tetras looks to of gone down. It must be the medication. None of the tetras never had a bent spine. Wish I had treated the tetras sooner.

Fish dropping. I've had a black Molly die in the night. It had a swollen belly so it could of been Dropsy.

Acraflavine that's in Myxazin is harmful to plants. So anyone using this medication I suggest you remove your plants.

The reason fcmf asked for your hardness is that you have (or had) both soft water and hard water fish, so one or other type will not do well.

The hard water fish are mollies; the soft water fish are everything else.

Fish don't get used to a hardness outside what they have evolved in. Soft water fish will appear to be OK in hard water but their internal organs will be slowly filling up with calcium deposits and they'll die earlier than they should.


Water changes should be at least 50% every week. It's not just nitrate and phosphate that build up, there is also a whole host of other chemicals and biochemicals we can't test for. These need to be removed, and water changes are the only way to do that.