Tetracycline/sick fish

Question
I have a tigerhead goldfish and a bugeye goldfish in a 20 gal tank.  My filter is large enough for a 50 gallon aquarium.  I thought my bugeye fish had tail rot and eye cloud as he started getting holes/tears in his tail and one of his eyes turned hazy blue.  PetSmart suggested T.C. Tetracycline.  So, I followed the instructions, removed the carbon filters and started treatment.  After the first 25% water change my tigerhead started going bezerk.  She was swimming extremely fast around and into the side of the aquarium, rubbing up against the stones, leaning up against the heater and hiding behind the filter tube.  Needless to say, she has lost the majority of her scales.  I thought the T.C. Tetracycline might be affecting her so I stopped treatment and put the carbon filters back in.  I meant to do a water change but was unable to as I ran out of time before some unchangeable plans away from my home.

This was on Saturday.  Today is Monday.  She now seems to be fine, eating and swimming around normally.  However, my bugeye still has the eyecloud, yet his tail has healed up.  I plan to do a 25% water change this evening.  Will the scales grow back normally?  What can I do about the eye cloud that won't affect the tigerhead.


Answer
Hi Debbie,

It's uncommon, but sometimes medications have different negative effects on individual fish.

Fortunately, your Goldfish's scales will grow back. Her scales should grow back in 1-2 months.

The eye cloud is caused by a combination of poor water quality and/or a bacterial infection. Perform 10% daily water changes until the problem clears up. If you do not have the time to do daily water changes, a 20% water change every 2-3 days will do the same thing. Dosing with an anti-bacterial medication, such as Maracyn, will help. Maracyn should not affect the tigerhead.

In serious cases, the eye may be damaged to the point that the eye is completely blind. However, that is not likely in your case, and you should still treat it.

I hope this helps, and feel free to ask me any other questions!

Good Luck, and Happy Fishkeeping!