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Freshwater Aquarium/A whole load of problems with my guppies


Hiya! So I have quite a few problems with my guppies I'd really appreciate your help in!

I was away for about a month and left my tank in the care of someone with instructions to feed the fish everyday and to top up the tank water after two weeks. This reason being the tank is pretty low maintenance and so missing a water change or two is fine and won't completely upset tank parameters (I also don't trust a person who has never kept fish in their life to do a water change). And since I live in a pretty tropical region, the water evaporates from the tank pretty quickly, hence the top up.

The thing is, I've done this before and went away for two weeks only instructing someone else to feed the fish everyday and I changed the water when I came back. There weren't any problems with that at all. No casualties, no nada. Everything was fine. The guppies are pretty hardy too.

I've no idea what this person did or if they even did the two water changes or overfed the fish but when I came back, four out of five of my guppies were sick. One female and all three males. I've done the appropriate water changes, and even restocked my plants because even those died (seriously did this person even bother?)

I'll start with the males. All of them have come down with fin rot, which I've expected but I sure wasn't expecting it to be this bad where the fins are torn and the ends are black. This, I've got experience treating with bettas and they're currently in a hospital tank with salt in it. However, one of the males is exceptionally pale and with dropsy. I've got no idea how to treat dropsy successfully so I'd really appreciate some input! Another male seems to have one side of his body slightly swollen than the other. I don't know if this is a serious problem or some genetic thing but otherwise he seems fine if not a little beat up with fin rot.

The other hospital tank I've set up is for the female. I've been obsercing her and she seems to have problems swimming down. When she does, she seems to be struggling a lot only to float back up again. I'm not too sure if this is Swim Bladder but she isn't swimming upside down or anything and she isnt bloated either. I've set her up in another tank since I didn't want her to be overstressed by having 3 males chase her. I have no idea how to treat or diagnose her so I've left her in a hospital tank with some salt until I can figure out what is wrong with her and get the right medicine. The other female is the healthiest of all the guppies so I've left her in the main tank. She has no problems so far but seems to be wayyyy too aggressive. I've discovered newly spawned fry in my tank; godspeed to them.

I'd really appreciate your advise on what to do with these fishes! Especially with dropsy and that female fish. Thank you and I look forward to your reply!


Hello Elizabeth!

After hearing your story, I suspect that the caretaker of your fish must have changed or added water from a contaminated source. Otherwise, it is not likely that your fish would be infected out of the blue unless they are aggressive and nip at the fins.

For the male guppies with fin rot, I do not recommend using salt as an effective treatment. Using proper medicine such as Tetra's Fungus Guard should be safer and more effective. As for the female guppy, it sounds she is suffering from poor oxygen levels in the water, over feeding, and swim bloat. This happens when fish are overfed flake food. I recommend daily partial water changes in the hospital tank, and an alternative foods.

Please vacuum the gravel or sand in the main tank and do a complete water change to get rid of the contaminated water once the fish recover.

If you have any other questions, please ask!


Freshwater Aquarium

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I can answer questions about betta, goldfish, aquatic snails, freshwater crustaceans, freshwater bottom feeders, and tropical fish. I have little knowledge on freshwater frogs/tadpoles. No saltwater fish/cichlids questions please! I do *NOT* know how to make Decor for tanks/aquariums. I can also help you if your fish is stress/sick and setting up an aquarium/fish bowl/tank/etc. I can also help you with disease/injuries/parasites/etc. I can also help you with compatibility of tropical aquatic animals.


I have 30+ years of experience with tropical fishes & bettas. If you have a question (sending a picture will help) just ask and I will reply as soon as possible!

I went to Stanford University (Graduated). Has a Masters Degree

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