Mystery Platie Illness.

[fishie1]

I have a tank that had 12 platies in it. A while ago it included tetras, which I found were the wrong companion fish after the local pet store advised me that I was killing my fish with too low a pH level for the platies (who had become ill). At their advice, I added significantly more conditioning salts to rectify this problem, which resulted in accidental genocide of the tetras. Since then, I just stuck to the platies with a high pH and lots of conditioning salts.

On the weekend I took a water sample to this pet store to have it analysed by all the standard tests and they advised me that my water was out of control with GH and to change 50% of the tank water and replace it with UNconditioned water, but to still use the water ager. I changed a further 25% the next day as the GH levels were still too high (23 drops.. about 400ppm?). Today I have lost 4 fish and a fifth is about to go. The only symptom is periodical loss of ability to swim (they float around like a leaf in the breeeze, then go crazy swimming around the tank) and a zinc-white colouring around their mouth. This has NO fuzzy bits like fungus, it is like just the skin has changed colour.

Stupidly, I also added 2 Kuhlii loaches before the first 50% water change and one died this morning, the other seems fine. Would a picture more helpful?!

Can anyone help me?! I don't want dead fishies!

 

[rdd1952]

I would trash the salt. I think that is most likely what is driving the levels up and most freshwater fish do not need salt. In the long run, it will do more harm than good. Of course, your tap water could be the problem. It is unusual though to have high GH and/or KH and low pH as you originally mentioned. Usually when the GH & KH are high, the pH will be also. Same usually applies to low GH & KH. Most fish, platies included, can easily adapt to a pH outside their optimal. If your original pH was in the mid 6s, the platies should have been fine. Trying to alter GH, KH or pH usually leads to far more problems than it solves.

 

[fishie1]

Thanks for the reply.

I don't think I should completely trash the salts, as our water is fairly soft ( about 55 ppm). I live in the country and our water is sourced from a river, and treated only with chlorine. The water is safe to drink, so it should be safe for the fish. I use water ager to get rid of the chlorine, and I do think I should still use a little salts.

Could it be the sudden drop in GH that made them sick? Even so, it doesn't really explain the blindingly white patches around their mouths. When I added the Kuhlii loaches, I added about 100ml of water from the pet store with them. The tank I bought from was full of healthy fish, however.

 

[rdd1952]

I have city water and my water is as soft as it gets. GH & KH are both 0. I've never used anything to alter them except for some crushed coral (about a teaspoonful in the filter pack of my 29 gallon) at one time. My pH runs in the low 6s but for the fish I keep that is fine. As I mentioned, most fish will do fine in any pH even if it isn't their optimal.

Actually, any sudden change in GH or KH can be harmful. Most common thinking is that pH changes are harmful but most likely it's actually the GH/KH change that does the damage. The white patches could have come from the LFS. Even healthy looking fish can still be carrying disease as they are usually only in the fish store a few days and they diseases may not have showed up yet. I'm not much on disease ID so can't really say what that might be. In any case though, it's always best to quarantine new fish for at least 2 weeks and preferrably 4 weeks before introducing them into your tank. Better to treat a few new ones than all of your fish. Also, it's best not not add any of the LFS water to your tank. Acclimate them as normal but once you are ready, pour them into a net over a bucket so you can discard the bag water.

Back to the salt, here is a thread with a very good post (#9) by Bignose about freshwater fish and salt.