Brute the Goldfish

[Auffle]

I have two 2" common goldfish (Stringbean and Brute) and one (Brute) has swam into the filter - twice! The first time he was fine, some torn fins and missing scales, but the second time his caudal fin turned brown and was split down the middle, he lost one pectoral fin and half of the other, and he's holding his spine funny. I turned off the filter (there was a second filter in the tank) do you think he'll recover well?

[ScottFish]

How are Stringbean and Brute doing? (Great names, BTW.) Have you found a way to safely cover the filter's intake better so they can not get into the filter?

[Auffle]

They're both doing well, growing fast. Brute can swim just fine despite his split tail fin and single pectoral fin.

I took the filter out that was causing the trouble; it was only in there as a source of beneficial bacteria as I had it running on a mature tank.

this is the filter that is still in the tank

[Diana]

In answer to your question:
Fish can usually heal fin damage rather quickly. Best thing you can do is to keep up the water changes so the NO3 stays below 10ppm, and lower is better. Vacuum the floor of the tank with special attention to any slow moving areas where microorganisms may gather.
If the injuries are deeper into the fish, into the muscles or went any deeper than a few scraped scales, then full recovery of the fin might not happen.
Also, injuries that compromise the slime coat can cause more problems, leaving the fish open to infections and fluid loss.

Note also that when goldfish heal they occasionally generate more black coloring at the injury site. This will gradually go away. To find out more about this look up Melanophore migration.

Goldfish are tolerant of salt. You could add some salt to the water at the rate of 1 teaspoon per 10 gallons every day for 3 days. That will bring the dose up to 1 tablespoon per 10 gallons. When you add the salt, do it this way: Blend the dose in a cup or two of water and add it to the tank a little at a time over several hours. When you do water changes add that dose to the water. If it is a 10 gallon water change, add 1 tablespoon to the water.
This is not very much salt, but it can help a fish that may be under stress, and injured. When you are ready to remove the salt do not do a giant water change, just do regular water changes and just add half as much salt for a couple of water changes, then a quarter as much for a few more. This will gradually lower the salt level over about a month, and give the fish plenty of time to adapt to the change.