Zebra Danio shaking, no appetite

tf1265

Here are the specs on my tank: 15 gallon tank, heated to 76, filtered. Live plants, gravel substrate. 25% water changes once a week (conditioned, plants fertilized).

Ammonia: 0
Nitrite: 0
Nitrate: 40 ( I know this is a little high, I'm working on keeping it lower)
pH: 7.6
moderately hard water

Stock: 4 zebra danios, 4 false juli cories, 1 male sunburst platy, 1 tiger nirite snail. They have all been living happily in the tank together for 6 months, no problems that I'm aware of.

The problem:

One of my danios, the smallest one, is acting weird. His dorsal fin has been down, he's had no appetite for 2 days, he's been "hiding" a lot at the bottom and staying away from the others, and he will often stay very still except for what looks to be involntary pulsating, like a little fish seizure.

There's no outward sign of disease that I can see, and I've never seen a fish shake like that involuntarily.

Any thoughts on what this could be? None of the other fish are acting strangely at all, and this guy just started yesterday.

Thanks!

GwenInNM

You should try to get him out of your main tank. Even a bucket with an airstone can work for a short time. Could be an indication of parasites, and you may need to treat. Best of luck. At least isolated he won't feel as stressed and won't infect others, possibly.

GwenInNM

You should try to get him out of your main tank. Even a bucket with an airstone can work for a short time. Could be an indication of parasites, and you may need to treat. Best of luck. At least isolated he won't feel as stressed and won't infect others, possibly.