I have a corner unit tank in my house that houses 5 neons, 3 glass catfish and 4 platies.

I've built it up gradually over the last 6 months and was going to add a few sword fish and a couple of guppies to complete my tank over the next coming months.

I used to keep tropicals ages ago when I was a kid, so know the basics about maintaining, i.e. waster changes, treatments, oxygenation, plants etc but I've never bothered to breed fish as I don't really want to.

So imagine my surprise when the OH shouts me down before and points to 4 diddy little babies swiming around my plants! I've googled all the breeds of fish I have and they look like platy fry!

On the one hand I'm very pleased that they have bred as it shows they must be being kept right, on the other I don't know what the hell to do!

Is getting a breeding box/net right? I can't see how I can stick on one a corner unit? Or should I get some more plants and hope for the best?!

Also, I know that if this keeps happening I'll have to take them to a shop or something to stop getting overstocked. I don't want another tank, but sure as hell won't be adding any more!!!

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First of all, sex your platies. If you don't want more fry, you'll have to separate the males and females as a long-term solution. However, even then, the females can store sperm from the males and use it for upto several months.

I'd advise removing the fry, as the Glass Catfish may take a liking to them. Breeding traps are crude but for a handful of livebearer offspring, they should be fine until the fry are big enough to be re-released into the aquarium. With that said however, a large number of fry will need a dedicated raising tank complete with a sponge filter, a highly varied diet and 50% daily water changes to keep the water quality at the optimal levels and to promote the development and growth of the fry.

Bugger!

Just spoke to a friend who's kept fish for a few years and he didn't bother removing his when he first saw them, most of them survived he says but he's done what you suggested and removed the males from his tank.

I certainly don't want more. There are actually 3, I've just seen them all, saw a reflection of 1 before, and thought there was 4.

Do you reckon a breeding trap will be ok for the time being? Going to have to do some research into sexing the platies as well although from looking at them at the moment I think I have 2 males and 2 females (femails looking a bit larger than the males). I might hand the boys over to my brother, as he doesn't have any platies in his tank. He has a 42 liter "cold" water tank, and I know platies are able to live in temperate water as well as tropical, so that might be a solution as I don't really want a second tank. Either that or I get a second small tank with a small filter and just use for this situation. I wouldn't need to light it or anything would I?

Off to pets at home or dobbies tomorrow then, don't think anywhere else will be open!!

**edit*** Hope the little beggars make it until then!!

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A breeding trap would be an adequate temporary solution for the fry you have now. Fry are able to conceal themselves within aquatic greenery however most will be picked off sooner or later; it's also much harder to keep an eye on them. Some livebearers can tolerate cooler conditions, however in my experience Platies should be kept at higher temperatures closer to 24-26°C.

Sexing Platies is fairly simple, look at the profile of the anal fin just before the vent. Males have a swept-back anal fin with a rod-shaped profile called a gonopodium, which of course is used for insemination. Females have a normal anal fin with a round-profile which serves no specific purpose. Platy fry can normally be sexed within three months.

A fry tank should be kept simple, with no substrate and the bare minimum of decor; a simple terracotta flower pot and 1-2 artificial plants will be fine. No lighting is required, natural daylight (not direct exposure to sunlight though) will be fine.