Spots on fish?

Question

We have a 10 gallon tank with mollys' in it. The tank is cleaned every weekend with a major water change at least once a month. Some of the fish have been developing spots over the last month or so. The lighter colored fish have white blotches on their fins, and the darker colored fish have black spots on their body and fins. None of these spots resemble salt, so I don't think it's ich/ick. The only way I can really describe what the white spots look like is spilled milk on the fish. Any ideas what this could be?

After finding more pictures online, I think some of them are dalmation molly's, which explains the black dots. I'm still confused about the white spots though.

They have never rubbed up against the rocks.

By major water change, I mean using the siphon to remove any of the nasty stuff from the substrate, and in the process, take out about 25% of the water. We've never completely emptied out the tank.

Answer 1

The white spots are most likely Ich. Ich is a parasite that burrows under the fish's scale and feeds off the fish's blood and flesh. The white spots you see are a cyst that the body of the fish forms around the parasite in an attempt to protect the body.
It basically looks like the fish has been rolling in salt - I know you say your fish does not look like that, but unless it is simply coloration developing on the fish... Look closely - is it a bump? Or is it just the scales? If it's just the scale, no need to treat; mollies change colours sometimes as they mature. If it is a bump, it's probably ich. If it is fuzzy, it;'s fungus, and you must treat accordingly with maracyn or maracyn-2.

If it IS ich, to treat, use salt (actually, if you don't already know, mollies are brackish fish and should always have some salt in their water) :) Get some aquarium or kosher salt, and add 1 tbsp per 5 gallons of water (so 2 tbsp for you 10 gal), disolved first in dechlorinated water. You can also increase the temperature to 80F to increase the speed of the ich's lifecycle. After 2 weeks, the ich should be completely eradicated ,the salt will gradually go away as you do your weekly water changes.

One last thing it could be would be injuries, like if the mollies are fighting.

Also, you say you do weekly water changes and once big cleaning a month. The water changes every week are enough cleaning, no need to do a large weekly cleaning other than the basic, wipe down the sides, etc.

Answer 2

I would never do a major water change in your tank! Infact I never changed the water. The water in my tank evaporates and I would clean the surface of the tank, clean the filters, turn the gravel, then add more water to tank. (make sure its the same temperture) I have never had any problems. I had a fresh and salt water tank and did the same for both tanks. It sounds like your fish have a bad fungus. Do they scrape up against the rocks and sand? If they do they have ICK.

Answer 3

Well it could be perfectly natural, or it could be a fugal infection. Many fish will change colors slightly at adolescence, so this may be it. If not, then it is fungus, and treat with melaflix or maroxy.

Answer 4

I'd take some pics and show them to the people at a pet store that specializes in fish. They would be better able to diagnose your problem than we can.

Answer 5

That's fin rot but there are drops that you can put in the water to get rid of it and worse case scenario they will go bottems up

Answer 6

Its ick. They will die from it if you don't treat the tank. And they may die anyway. Sorry. It spreads too from fish to fish so don't put others in til its gone.

Answer 7

You got a disease in the thank, use fixacure

Answer 8

Fungus.