Silver Dollars Are Sick

My silver dollar's fins have been looking really funny for a while so i researched it and guessed that they had fin rot. so i treated them with "Melafix". it says that it treats fin rot so i got it to use. i have included pics of them. they also have something else wrong and i cant figure out what it is. would you please help me?

Tank size: 25 gallons
pH: I dont have a test kit ( im still a newb at fish stuff, but learning)
ammonia: ditto
nitrite:ditto
nitrate:ditto
tank temp: around 78-80 degrees F

They seem to act perfectly fine maybe a little laid back but other that that they seem to "act" fine. They look like they should be dead already they look like something is eating their flesh and their fins are almost gone.

Volume and Frequency of water changes: about 25% every other month

Chemical Additives or Media in your tank:

Tank inhabitants: Two silver dollars, two bala sharks, two tetras and a scum sucker ( i think it is called a peko?)

Recent additions to your tank (living or decoration): nothing

Exposure to chemicals: ???

Well firstly you need to test the water. We gotta know what the readings are because that will help you and us rule out different diseases. Your tank is also overstocked which could cause a problem and the reason I say that is because Bala Sharks can get to 18 inches. Those silver dollars definatly have fin rot, and I can not say for sure what else they have wrong so i'm not going to guess but as of now judging by the looks you need to quarantine them and treat with a very very strong antibiotic!! All I could find on that your fish might have is here on this link. Letter I on this link might be what it is...

First off hello and ......Sorry this had to be your first post though.

Silver dollars:Awe man they do have fin rot, however they have something else major too. I would suggest possibly putting them down as they seem to be in really bad shape. The fish in the second picture looks to far gone I believe. It seems as they have a bad case of bacterial diseases.

Also a note about silver dollars they can reach to about 8inches in size.

Chemical Additives or Media in your tank

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This would be things such as carbon that you put in your filter.

Tank inhabitants: Two silver dollars, two bala sharks, two tetras and a scum sucker ( i think it is called a peko?)

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The bala sharks will definatly need a bigger tank. They can get up to a foot and bigger.
As for the scum sucker, that would be a Pleco...just for future reference.

Exposure to chemicals: ???

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This would be things such as candles, or fragrances sprayed or cleaners.


Well good luck!

Hey, thanks you guys. i think your right about what they have as in the cosia infection. This is the biggest tank that i have ever gotten ( the 25 gallon one) so i wasn't sure what all to put in it. i have just within the last hour or to set up a 10 gallon tank and I'm not sure what to put in it. i did have a 5 gallon tank with a two dwarf puffers in it but one died and the other seems to be doing fine now. i think the other died because it wouldn't eat flake food, so we started feeding it bloodworms after the first one died thinking that it might have starved and its doing fine. we transfered it over to the 10 gallon and also put in the two tetras with it. i was wondering if you can put in other normal sized puffers in with the other three in that tank. and thanks again on all the help. i will try to get a testing kit as soon as possible too.

Here are some profiles below on your fish.

Silver Dollar Fish

Bala Shark

Tetra's Not sure what type you have but there are a few on here to look around at.

As for the dwarf puffers there are millions of different kinds of them. So try to do a search on the web for the puffer and see if you can find a type that you have. Puffers can and may be aggressive toward the tetra's.

I would not buy anymore fish until you can get all this sorted out. As of right now your overstocked with the ones in the 25gallon tank.

Try to remember about 1inch of fish per gallon of water.

Good Luck