I have kept my goldfish for almost 2 years now and he is very healthy, happy and rather large (4 inches roughly) and I have had no probelms with him (except haing to upgrade his tank size twice!!!)
I have recently invested in a traopical aqurium. I added the water, plants etc for approx 10 days then added 5 platys (as advised by the garden centre) they were all still alive 72 hours later so I was advised to add a few more fish. My tank is 100 litres so I added 5 guppies with fancy tails, 2 rams, and two rainbow tetras 10 days ago. I have since lost 3 of the guppies and another looks swollen and has slowed down when swimming also staying at the top of the tank. I'm quite sure he will die shortly. the other fish for that matter appear lively, active and happy! I read about dropsy and think it may well be that To add to the problem the fish infected fish also seems to have ich which I am currenly treating for with both salt & treatmt. will my other fish get dropsy? Help

Your tank really should have been cycled before any fish were added and adding that many that quickly would definitely cause a huge ammonia spike. Your tank stocking was really at the limit for your tank size before the losses you've had now.

You need to get a test kit and check your water for ammonia, nitrites and nitrates. Doing some partial water changes immediately may also help.

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