Neon Rainbowfish Behaviour & Feeding Problem

[luckyjonah]

Hello everyone

I am new to fiskeeping and have recently set up a 90l tank with a gravel base, some slate and stones, a couple of swordplants, some cabomba and a sickly vallis. After a 4 week fishless cycle the first fish I have added are 6 neon dwarf rainbowfish. My LFS (who have been very helpful) advised me that they couldn't sex them as they were still too small at about 2cm - I asked for 3 with red trimmed fins, and 3 with yellow trimmed fins. I have since re-read my bookmarks about rainbows and see several people saying the sex can be determined by colours - can I be sure I have 3 male and 3 female or is it not that simple?

After putting them in the tank I kept the lights off and didn't feed them. They mostly stayed down by the gravel in a tight group. By day 2 with the lights on they have started moving about towards the middle levels and generally seemed happy so I went to feed them - I turned off the filter and put in the flake food, but they all got scared and hid in the bottom corner and ignored the food... so after a while I put the filter back on and they relaxed and went after the flakes as they fell down - however, in general they seemed to spit them back out and they have just left them on the gravel. Do I need to worry about this lack of appetite, and/or are they fussy eaters?

My other problem is that 2 of the fishes (red) have started swimming very quickly towards/into other fish - it looks like sometimes they bump their noses into them. Sometimes they seem to swim round the front to go nose-to-nose, before moving to their side (head-to-toe), and kind-of "rotating" as a pair. Most of the time these 2 red rainbows have got erect top (dorsal?) and bottom fins. I feel really stupid asking this, but is this normal behaviour, aggressive behaviour or are they just chasing/harrassing the ladies?!

Any help would be appreciated!

 

[ollyhtafc]

My other problem is that 2 of the fishes (red) have started swimming very quickly towards/into other fish - it looks like sometimes they bump their noses into them. Sometimes they seem to swim round the front to go nose-to-nose, before moving to their side (head-to-toe), and kind-of "rotating" as a pair. Most of the time these 2 red rainbows have got erect top (dorsal?) and bottom fins. I feel really stupid asking this, but is this normal behaviour, aggressive behaviour or are they just chasing/harrassing the ladies?!

Any help would be appreciated!

This might not be of any help but some fish breed that way...at least my minnows do,they seem to pair off, then if any other fish come near they chase them off )kind of alpha male type thing).And from my observations the erect fins can indicate aggression or breeding, or simply establishing a heirachy.

 

[Andy7000]

Heard this also about the neon. Hi by the way.

 

[n3ont3tra]

I have a group of three and one of them I suspect is a female. She has a yellow tail and the other two chase her around lol. Mine don't like flake food all that much either. Also, the behavior you're describing seems normal.

 

[jennybugs]

I have these little fish too. The yellow finned ones are female and the redder finned ones are males.

They 'flash' their fins at each other all the time and it's natural behaviour, as with any rainbowfish.

Do you crush your flake food first before feeding? Rainbowfish have big mouths but very small throats so it may be that they can't physically swallow the food.

I don't turn filters off when I feed my fish and they seem to manage just fine.

Hope that helps a bit

 

[luckyjonah]

Thanks for the replies.

They have settled in a bit more now, and I found that by crumbling the flakes a bit to make them smaller they were much happier - in fact they preferred mid/low levels and waited for small pieces to come straight to them from the pump which I leave on. They still won't touch the full-size flakes and bizarrely they also spit out the white ones (fussy eaters I guess!).

I have now introduced 3 red guppies and they are all getting along fine. In fact, the guppies appear to have kick-started the rainbows' appetites and the tank now resembles a cartoon piranha feeding session when I put the flakes in, all the fish darting to the surface and fighting over the flakes. Much better!

All sorts of sparring and showing off last night in the tank - 2 males were constantly sparring whilst the 3rd male sat back in the plants and showed off his fins to the 3 admiring females - just like real life eh!

 

[n3ont3tra]

My rainbows will take a big piece of flake food and spit it back out in lots of tiny pieces. Does anybody else's rainbows get scared when you walk up to the tank?

 

[jennybugs]

Yep, mine get a little spooked first off then when you've been there for a bit they calm down. It's like Mission Impossible trying to get good pics of them though