Can somebody help please

[JustinWong]

Hi im new to the hobby and i bought a 6 gallon tank about 2 months ago. my tank contains one 3 striped damsel, 1 camel cowfish, and 1 green chrome damsel, 2 hermit crabs and a snail. just recently i believe my damsel has fallen ill. his symptoms consists rapid breathing and leaning on the bottom of the tank. i suspect it is ICKE but i dont see white dots. CAN SOMEONE PLEASE HELP?im scared to lose my only 3 striped damsel.
WHEN I FIRST GO IT

NOW

 

[kingfisher62]

If I am not mistaken a cowfish can produce toxins when stressed. three striped damsels can be quite aggresive especially to something like a cowfish. So that is a possibility.
See if a water change helps.
Also, How long has this tank been running?

 

[tahoe61]

The best thing you can do for your fish, is get a larger tank or seriously cut back to 2 fish.

In a 6 gal tank two fish is about all it can handle. Try and stuff more in there and you will have on-going problems with disease related to stress and over crowding and poor water quality.

Damsels are one of the most aggressive fish you can buy and they will have territory issues even in a larger tank, so 6 gal is just asking for trouble.

The cow fish really belongs in a larger system as well.

 

[gweston]

I don't see ick there (but can't be certain). I suspect it is parameter/stress related more than ick. But regarding what you have going on right now. Test out your water params. At least test for these values.

Nano tanks, which a 6 gallon is, require some close parameter watching. Just because at smaller water volumes, parameter changes occur must faster than with a larger volume of water.

salinity/SG
ammonia
nitrite
nitrate
ph
alkalinity

What sort of filter/system do you have? Could adequate aeration be an issue? If your parameters (above) are on the mark. Try improving circulation/aeration. How often do you do water changes, and what quantity?

Regarding fish population. I'd concur with the others to reduce the fish down to 2. To give you an idea, I have 4 fish in a 29gal (+15gal sump) system. I may be able to add one more due to all the liverock, skimming, filtration, etc that I have running. But I won't.

I believe typical Cowfish can grow very large. Upwards of 12"+. They do have toxins and tend to not be coral/reef friendly. Not sure which one you have though... so can't tell for certain it's maximum size. If the cowfish dies, be sure to get it out as soon as possible. Yes they do have toxins in them.