Danios - larger ones chasing and nipping the others.

[Littleover]

Hi, we've had our 14ltr kids tank for 2 months now and started off with 4 male danios, one being slightly larger than the others. First couple of weeks OK but noticed that the bigger one kept nipping the others. Over the next week it picked on one fish until the poor thing hid in the plants. I made sure it fed but it and the others gradually got more distressed, frayed fins too and they all died. Have a friend with a similar tank and she took him in. He's doing fine there and hasn't picked on any of hers! Got another 3 danios today and the same thing is happening. Within a couple of hours one of them is stalking and going for the other 2. Is it a breed trait or a size thing? Should I add a different breed? Such a shame as the scared 2 are hiding and it looks like we only have one who is swanning around like he owns the plank. I had a tropical tank with a wide variety of fish for 7 years and never had this!

Place not plank!

It's normal for shoaling fish to sort out a pecking order. There are a couple of problems with what you're experiencing with yours though. Firstly your shoal size was too small- adding more fish normally solves this by spreading out aggression so you might see a change...

Except your tank is far too small, and that is the second problem. Because they are so crowded, you will see a lot more aggression. Danios are very active, zippy fish and they need space to spread out. I would recommend a tank size of about 70 litres minimum for the fish you have. 14 litres isn't really good for any fish.

Sorry if that's not the news you wanted to hear :( but there's really no way to solve the behaviour issues in the tank you have.

Thanks EauRouge, I wish I'd tried fishnet first!

Danios are very active so need a lot of space, you would have been better with some tetras or endlers as they don't grow quite as big, really a tank under 40ltr is pretty useless unless you are keeping shrimps or a betta, even then it's tricky to keep the water in good condition . I would get a bigger tank, you can usually pick them up for next to nothing 2nd hand, ebay often has bargains and I often pick up tanks from my local tip for a few £.

second all the Eau has said.
Your tank is really far too small to reproduce anything like natural behaviours in any fish,apart from maybe a single male Betta.
What I would do would be take the fish you have back to the shop and start again with either a bigger set up, or if thats not an option, either a few snails and shrimp.