Mysterious Tiger Barb Problem

[cyclonerex]

I have a fairly new community tank - 20 gallon, with 4 small tiger barbs (about an inch in length), 7 danio zebras, 2 dwarf gouramis. The fish have all been active and appear healthy. Yesterday, I had a hatchet fish die and another today (I only had 2). This morning, a Barb was dead and another was looking bad. It was swimming almost nose straight down. It's mouth was a little red. The other two don't look bad physically, but they are swimming very uneasily. Just look like they are very unhealthy. They don't appear to have anything wrong color-wise.

The Ammonia Nitrate levels are ok. Ph is between 7.2 and 7.4. Any ideas?

 

[fluttermoth]

Tiger barbs swimming head down like that is usually a sign of high nitrites; have you checked those?

In any case, the first thing to do if you lose a fish is some massive water changes (warm, dechlorinated water, of course).

How long has the tank been set up and was it cycled at all, and if so how?

 

[cyclonerex]

Tiger barbs swimming head down like that is usually a sign of high nitrites; have you checked those?

In any case, the first thing to do if you lose a fish is some massive water changes (warm, dechlorinated water, of course).

How long has the tank been set up and was it cycled at all, and if so how?

Don't have a way to check nitrites tonight. Tank has been running about a month. Cycled for 8 days prior to adding fish. I think that is what you're asking...

How do you make water changes? i don't really have access to dechlorinated water unless I use chemicals to dechlorinate.

 

[Smells a bit fishy]

After a month. Could be a possibility that your nitrites are high. The nitrogen cycle is this in it's simplest form. Fish make waste. Waste turns to ammonia, then good bacteria converts it to nitrites, then more good bacteria converts it to nitrates.

To do water changes take water out, then fill it up using same temperature as te tank by using a little hot water. And use a chemical for dechlorinating water. I use tetra aquasafe. But there are many on the market.

Am I right in saying you havn't done a water change since you set up the tank? Most beginners make this same mistake, myself included. When doing a fish in cycle you need to keep ammonia and nitrites less then .25ppm on each. Normally means 50% water changes daily for a month, or until they stay below those levels.

Do a 60% water change now and get an API resting kit, you can pick these up for £25 online or I got mine from my LFS for £30 as I needed it asap. Get the liquid testing kits as they are far supreme to "dip stick" types.

I hope this helps you some what