Australian rainbowfish (Melanotaenia fluviatilis)

iamntbatman

I picked up four of these guys the other day for my 29g community. The tank also contains my breeding krib pair as well as six or so of their half-grown offspring.

The fish are about 2" long right now, so I'm not sure I can sex them. One seems to be the dominant fish in the group and has a stronger coloration on the edges of its fins, so I'm assuming this is the male while the other three are female.

I'm likely going to pick up more of these in a week or two to round out the school (and the tank in general). What sexes should I try to pick up? Should I aim for the typical 1:2 ratio for males to females, or do rainbow ratios work differently? I'm thinking I want a total of something like 7-8 fish.

These are my first ever rainbows and so far I'm quite liking them. They stay up near the upper areas of the tank for the most part and don't school really tightly but seem pretty relaxed. The kribs also pay zero attention to them, which is a good thing.

So, any advice on these guys would be appreciated.

aunt kymmie

I'm surprized no one has posted to this thread, I know many of our members keep these same fish. Got any pics??

iamntbatman

Not yet. I think I'm gonna wait until I increase the school size a bit so I can get more of them in one shot. Sometimes I see all four swimming together as a group, but more often I see two sort of swimming off on their own while the other two swim together. The pair that swims together includes what I'm guessing to be the dominant male in the group (I'm not sure on the sexes but it sort of seems I've got just the one male and three females). Hopefully increasing the numbers will help encourage a better group dynamic.

I'm really liking these guys so far, though. Gorgeous fish, and they aren't even fully mature yet!

iamntbatman

Just an update: I tried to get more of them today but due to all of the snow the LFS hasn't been getting shipments so they were fresh out. Apparently they've got another shipment due in Friday, so we'll see.

The four are still doing great. I'm pretty sure now I've got two males and two females, though the one male seems to be the dominant fish in the group. Every once in a while he'll chase the others a bit but not for more than a second or two, and much of the time they'll all swim together as a group. They also seem completely oblivious to all of the Kribensis drama in that tank (I really do need to get rid of these "fry", haha).