My violet goby died today .____.

[Syntria]

I guess I didn't take care of him well enough.

His started going to the top for air. (I've had him almost a week) and until the last two days he was just acting werid, but he started getting week and just...wrong seeming, the way he swimmed and moved seemed off. His gills became inflamed, and his eyes whited over a little. his belly was kinda bloated, and soon his eye sockets sunk in a bit. He died ._. and had little like...seizures. you could see the muscles along his stomach twich, but his gills werne't moving. I'm pretty sure he was totally dead, but just...I don't know, it was creepy ._. he also had yellow/red fluid's coming out of his private that didn't look like like they should.

._. anyone have any idea what was wrong with him? and should I fear for the rest of my tank?

My tank is 20 gallons
A filter
A pump (for current)
1/4 inch blue gravel
Water - Conditioned, and very slightly salt. I put about one table spoon for 20 gallons intead of 1 for every 5 like it said I could/should.

Fish
2 very large goldfish, I'm unsure the type
1 silver stripper catfish
1 pe...suckerfish
1 small black gold fish

I had another gold fish but it died to. I'm a bad person I guess x_X (I've never had a fish tank before)  

[BluDragon35]

Violet goby? Hmm...from what I know of this fish, its pretty sensitive to the water condition. Plus, its sorta weak to begin with, you might have picked out a fish that was already sick. If your other fish don't show any symptoms then I wouldn't worry too much about them. Looking at the symptoms...its most likely fis bloat....but I can't be too sure without seeing the fish myself. sweatdrop

Well, I'm sure you're doing your best in raising your fish. If you have anymore questions about your fish just ask! ^_^
Next time I'll try to answer a lot quicker. sweatdrop  

[BluDragon35]

Also, it might depend on how long you've had your tank running. New tanks usually don't take well to a lot of fish.  

[SquishyAngeh]

For what you have 20 gallons sounds really small... It might have been over crouding....large gold fish really need about 20 gallons each...not to mention that you have more fish in there as well. It coulda been a mix of overcrouding/poor water quality coming from over crouding/ and stress...  

[Amidala02]

Okay, you're not a bad person, just new to keeping fish and making a lot of mistakes the same as anyone else will. I'm going to tell you the places where you're going wrong, so that you can fix them before you do anything else and then things should get better for you.

Firstly you have it right that the violet, otherwise known as dragon, gobies need salt. They need about 7.5 teaspoons for every 10g of water.

They are also aggressive and sometimes predatory and require a long tank of at least 120cm in length, because they can attain 60cm in length when full grown.

They are also very sensitive to poor water quality and will stop feeding and starve themselves if stressed.

From the symptoms, I would suggest that the violet goby had an internal bacterial infection and quite a nasty one at that. This would indicate very bad quality water. You should purchase the following test kits if you haven't already and check your water!

Ammonia
Nitrite
Nitrate

I suspect that you will have high (anything above zero) ammonia and nitrites and to get these down you will need to do an immediate large water change, then test on a daily basis and keep changing the water until the ammonia and nitrite reach zero.

Secondly, you are most definitely over crowded. You probably have comet goldfish and they can reach a foot in length each. You need 20g for the first fish and an extra 10g for each additional fish - therefore you are way overstocked.

Next, the goldies are cold water fish and the others are tropical, so you need a heater.

And then theres the catfish, most are scaleless and cannot tolerate salt in their water - it burns them.

Last but not least - have you ever heard of cycling a tank? If not, please check out these two articles that I wrote and you'll get a detailed lesson quite quickly!

The Nitrogen Cycle
Cycling a Fresh or Brackish Water Aquarium

Good luck!