What's Wrong With My Platy?

Hiya,

My platy I thought was pregnant, you could see the black area that you do in guppies, noticed other platies chasing her around last night (thought she was going to give birth), tonight have just fed them and noticed a reddish lump coming from her. Please help.

Tank size: 175 UK litres
pH: 7.5
ammonia: nil
nitrite: just under 0.1
nitrate: over 200 (I know, am trying to sort it - new tank?)
kH: unsure yet, will know tomorrow
gH: same as above
tank temp: 26 C

Fish Symptoms (include full description including lesion, color, location, fish behavior): fish behaviour is normal, eating as normal.

Volume and Frequency of water changes: 10% weekly

Chemical Additives or Media in your tank: water softner, salt (planning to omit this), dechlorinator, ph minus

Tank inhabitants: guppies, blind cave fish, upside down catfish, platies, various tetras, kissing gourami

How may fish do you have in the tank and what type, as that nitrate reading is really high.
The lump look bacterial can you issolate her for treatment.

You'll need to do more than 10% water changes once a week to get that nitrate level down. I'd do 30-40% straight away, give it a day to rest then do another and test again.

Thanks, the tank isn't overstocked but is a new tank as the old one leaked so has a lot of new water in it, and a new filter along with the old one.

Today another platy has swelling round its eye - the eye looks normal but is in the middle of a huge swelling. Can't get a picture yet.

I can only isolate in a breeding trap - I have a plastic one but I guess it wouldn't be any good as I'd still be treating the whole tank would I?

Sounds like popeye to me.
http/www.flippersandfins.net/pop-eye.htm

Thanks,

I've treated with Myxazin for bacterial problems but the fish died, also the other one with the eye problem I can't find so I think it's died too.

Another fish has what looks like a dusty appearance so I think it's velvet.

I can't treat with Protozin until 4 days after treating with Myxazin so I'm worried I'm going to lose loads of fish

Remeber to do a big water change and run with with carbon in the filter befopre admisitering more meds.

Somepeople think your better off letting fish die until you 100% sure what your dealing with, Often just trying different things can make things even worse

Sorry R.I.P.
Velvet can look like a talc dusting on a fish, or a yellow to golden varnish.