Rainbow shark acting weird.. help?

[Super Nova]

I’ve had a rainbow shark for 3 days now.. he still hasn’t turned fully black and he barely swims around. He’s in one position floating for hours and I’m concerned something is wrong. I’ve seen him eating algae but ever so often.

My tank is 25l (I am aware this is small, I will upgrade to a bigger tank soon)
I’ve had it set up for over a week before putting him in.
My nitrate level is 40mg/l
My nitrite level is around 0.5-1 mg/l
Everything else is perfectly controlled.
I am aware my nitrite level is high and I am in the process of trying to lower it, I’ve added Aquarian salt and did a 30% water change yesterday.

Is there anything else I can do? Or any possible reason why he’s doing this? I am very worried that he will die if I don’t do anything soon.

 

[Super Nova]

Well.. couple hours later discovered he has come down with Fin rot.. my only worry is that I purchased him with this disease already present.. is this a possibility?

 

[SeanTrollope]

right so your problem is that the tank is uncycled. this causes severe stress any thus the fishes conditions deteriorate very quickly.

 

[Super Nova]

I found that my ammonia is quite high, I also got some treatment for the fin rot. Finally found out what’s been going wrong and I’m in the process of mending everything.

 

[fluttermoth]

You'll need to be testing for ammonia and nitrite at least once a day, and you'll need to do enough water changes to keep them both as near to zero as possible; that might mean having to do more than one water change a day.

You really need to get this fish into a bigger tank ASAP. Keeping fish in tanks that are too small will stop them growing properly, leading to long term health issues; if the fish even survives that long. A larger volume of water will also mean that toxins take longer to build up a dangerous level.

 

[SeanTrollope]

And thus things are much easier to control and problems can be detected and prevented much earlier

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