fishy disease?

Question
I have a 30gallon tank
I have 3 beta fish and 3 cory catfish in it

One of the catfish just started to look weird.
the strange mark on its little head resembles an white "cut" and its eye is white and a little swollen and red on the gills.
Could he have been hurt by another fish, or is this a disease?
I am going to separate him from the others regardless.

thx

Answer
Hi Kayla,

The wound on his head is most likely a physical injury, that may have become infected with a fungus or other disease. Do you notice any wavy, cottony strands on the head? If no, then you can rule out the possibility of a fungal infection. Isolating him/her from the other fish is a good choice.

Your catfish may have been injured by crashing into a rock, ornament, etc. Fish often do this when startled, for example, if someone taps on the glass or makes a fast movement in front of the aquarium. It is unlikely that the Betta fish or Cory Cats would have injured it, as Cories mind their own business near the substrate.

Since I do not have a picture, I cannot diagnose the disease, but here are some suggestions.

If you suspect that your fish has an infection, I suggest treating it with an anti-bacterial medication available from your local fish store. These include MelaFix, Sera Baktopur, Maracyn, etc. Even if the wound is not infected, the medication will prevent an infection, which is very common with injuries. Dose according to the package, and remove the carbon from your filter. Before you add the medication, change about 40% of the water first, as you will not be doing water changes for a few days (due to the medication.)

If you do not feel that medicating is necessary, change 20% of the water daily too, as this will reduce stress and promote recovery. You can add a dose of water conditioner too, as this will also reduce stress and aid the fish in recovery. Be patient - time is often the best method for healing.

Good Luck - I hope your fish recovers.