10 gallon tank with odessa barbs

Question
Hi, I work at a public library and we have a ten gallon tank that until recently was stable with 2 female odessa barbs, one female swordtail, and two banjo catfish. The barbs chased eash other a lot, and sometimes the swordtail, but left the catfish alone. The swordtail just died (about 3 years old) and now the barbs are behaving strangely, jumping at any movement near the tank and they are not chasing each other much. I've read that barbs should hang out in groups of about 6 or more but this seems like too many for a 10 gallon tank. Do you have any suggestions?
PS the kids love the fish tank (and loved the swordtail) and we want to keep it a success!

Answer
Hi Kurt,

This is Nicole Putnam, answering your question from the Question Pool repository. Your question really caught my eye - I also work at a public library and keep odessa barbs myself! Funny that, huh?

These are lovely barbs, I don't know why they aren't more popular. Prettier and better behaved than tigers, they are tough - barbs in general have a reputation for this - so they make ideal tanks for new hobbyists. The only thing is that they can be quite skittish. I will tell you what can help with this, but first I must say this...

Swordtails streamlined bodies are an indication of one thing: these fish are meant to swim fast! A 10 gallon tank is much too small for them. A 30" long tank (a 29 gallon or 20 long) would be the minimum, and even this is really too small...a four foot tank is what gives the best success, although you must be taking great care of your tank since swordtails rarely live beyond 3 years. Pat yourself on the back!

Now, on to the odessa barbs. I have a 29 gallon (30") tank with 5 odessa barbs, 6 bronze corydoras and 8 zebra danios. I got the zebra danios because of the exact problem you report - odessa barbs are skittish, unlike their gregarious lookalikes rosy barbs. They helped a great deal by acting as dither fish (you can Google that term for more info). While they still "run for cover" when I turn the light on (they are in a room that gets no ambient light) they are less skittish during the day. Before I got the zebra danios, they were tripping over themselves hiding when I came around! Now they are more likely to beg for food, as the zebra danios do. By having these top dwelling, fast fish constantly patrolling the top, they feel it is safe to come out and will be less likely to hide and be jumpy.

It's important to note that the behavior you report can also be caused by water quality issues, so check your water to make sure that it registers 0 ppm for ammonia and nitrite, and less than 20 ppm for nitrate. As long as the pH is stable, it's fine. None of these fish are too fussy about water chemistry, except for the late swordtail - your water must be hard and alkaline to have kept it healthy.

If you ever have an opportunity to upgrade, I would definitely keep at least 5-6 odessa barbs. This would be fine for a 30" tank or even a 24" tank if you kept a close eye on water quality. In your 10 gallon tank, since you already have the odessa barbs in there, I would add one more - but know that 10 gallons is really too small.

Great fish for a 10 gallon tank include neon tetras, rummynose tetras, harlequin rasboras, and female bettas (provided they are kept with peaceful fish). Some people have success with 10 gallon guppy and zebra danio tanks, but I wouldn't recommend it - these fish need at least 24" to not be feisty and have room to swim. Single male bettas are also great for 10 gallon tanks, perhaps with a mystery snail tankmate. Sometimes the long flowing fins of male bettas are a temptation to otherwise well behaved fish, and male bettas can be aggressive, so keeping them in a community setting is tricky.

Here's a great article on stocking small tanks:
http://www.wetwebmedia.com/ca/volume_5/volume_5_3/stocking.htm

So, in short - review water quality to make sure it is up to snuff, since this can cause strange behavior. Add one more odessa barb (most fish work better in trios than duos, although schooling fish *ought* to be kept in groups of 6, that much is true) and maybe add some dither fish to help bring them out. Zebra danios and small, fast tetras such as bloodfin tetras work well for this purpose. There is lots written on dither fish, so just Google away!

I hope that helps, take care. It's nice to meet a fellow librarian!
Nicole