# Zebra danio swimming strangely - diagnosis?



## Avocado Man (Mar 6, 2010)

Hi all,

I have a 20-gallon freshwater tank, with six danios, five platys, and 2 ottos. Everything has been going fine for about a year, and I do 20-25% water changes once a week.

Today I noticed one of the zebra danios (the largest one) hanging out in the corner of the aquarium, hovering close to the surface (but not gulping air). His dorsal fin is skimming the surface. Every now and then he will chase another danio, but at a strange downward angle (head lower than tail). Then he will quickly return to his spot at the surface.

Nothing appears to be wrong with his body - i.e., does not appear to be swollen. All the other fish are fine. Anyone have any ideas on what's wrong and how to fix it? I'm about to do another water change in the meantime.

THANKS!

Avocado Man


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## J-Pond (Jun 8, 2009)

It sounds like his swim bladder or maybe just old age.


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## snail (Aug 6, 2010)

check your heater isn't stuck on. hot water causes low oxygen and fish hanging out at the top is often the first sign. Have you tested ammonia, nitrites and nitrates?


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## Avocado Man (Mar 6, 2010)

Thanks to both of you! 

@snail: All of my levels tested out ok (nitrates, nitrites, etc.) Tank has been fully cycled, etc. Heater seems to be ok b/c my thermometer reads 78 degrees.

I think J-Pond was right about swim bladder. I did a little research on that, and found that people recommended feeding peas. I have been doing so, and every time I do that, the danio is able to swim around lower in the water column.

He's not 100%, but better than before. I am hoping that mixing in peas more often in the diet (as opposed to just tetra min flakes) will be good for all of them.


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## majerah1 (Oct 29, 2010)

A good way to eliminate the issue is to feed pellets instead of flakes.


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## jrman83 (Jul 9, 2010)

All my fish love peas. They go absolutely crazy over them when I put them in the tank. I have never seen compettition in my heavily stocked tanks until the days I put peas in. Fun to watch and its healthy.


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