white spot on fish

Question
We have a 30 gallon tank with 1 green barb, 2 tiger barbs, and 4 rosey barbs. We just did a partial water change this past week-end. One of the tiger barbs is swimming funny and has a white spot on his tail fin. Do you know what it could be and what should we do. We changed the filter (the kind that Wal-Mart sells)when we did the water change.

Answer
Hi Debbie;

If it looks like a speck of salt, it is a parasite called "Ich" and there are probably more in the tank that you can't see. Go to your local fish store and buy a medication for it. Also get some aquarium salt. Aquarium salt weakens the parasite while strengthening your fishes' slime coatings. This helps your fish fight off the little nasties. It is also helpful to turn your aquarium heater up so that the water temperature slowly rises up to 82f. The higher temperature causes the parasite to go through it's life-cycle quicker so the medicine can kill it easier and also weakens the parasites. Keep in mind that you may see more spots after you start using the medicine. This is because the medicine can't kill the parasites while they are still inside the spots on the fish. They have to progress to the next stage when the spots burst out into tiny baby parasites that swim in the water. The medicine then kills them. The ones you will begin seeing were already embedded in the skin, they just didn't show as white spots yet. The medicine will kill others in the water that aren't attached yet in the first couple of days too. Just keep using the medicine for at least a week to be sure they are all killed.

If the spot is more like a blotch and looks bigger than a salt speck, he may have been injured by the other tiger barb. Tiger barbs can be very aggressive to each other when there aren't enough of them. They distribute their aggression to several fish instead of one being dominant over one other. As long as the tank isn't new, you could add another two tiger barbs. New tanks need to get through the Break-in Period, also know as "Cycling" before having very many fish in there. Here is a link to my article about it to help you know more about it before you add more fish;

http://www.xanga.com/Expert_Fish_Help

Good luck and I hope everything goes okay. Followups welcome...

At Your Service;
Chris Robbins