I'm not sure if I am posting this on the right place cause I'm new here :)
I've got a +/- 26 (?) gallon tank (100 litre) with 6 zebra danio's, 5 guppies and about 15 shrimps (hard to count, they keep hiding). I'm kind of a noob, so I'm not sure if its normal, but at first my zebra's were very lively. swimming al over the place and almost impossible to count. some time ago, 2 zebra's died, probably of old age, I got them from a friend, and she told me they were about 4 years old. Now I have six left. Lately some of them started behaving, i don't know, lazy? Just hanging around, not on the bottom or something, but not doing much either. I noticed that they have slightly bent spines, atleast if I compare them to the others. Also their bellies look strange, I made some pictures
does anyone know if they are sick, and if so, what I should do? The rest of my fish are doing fine.