Lost a fish...

Hey guys,

I just lost one of my Banded Sunfish to a nasty wound that ended up infected with some kind of bacteria or fungus… Unfortunately I didn’t notice the wound until the fuzzy white stuff had covered half of his body and he was struggling to breathe. As soon as I noticed his symptoms I ran out to my LFS and picked up a 5.5 gallon tank so I could isolate him from the others and attempt to treat his injury/illness. Being cheap like I am I decided against picking up an additional HOB filter and took one of the two established AquaClear 30 filters off my 20 gallon long and slapped it on the 5.5 gallon tank as a temporary solution. I have been monitoring the main tank since I removed him and so far none of the other fish have shown any signs of injury or the disease. As of last night they were all eating and swimming like normal.

Anyway, now that the fish has passed I’d like to clean up the "hospital" tank and store it away for future use. I’d also like to return the AquaClear 30 filter to my main tank ASAP. My question becomes, how should I go about the tear down/cleanup process? I figure I will man up and purchase a smaller HOB filter for any future use on the 5.5 gallon tank and just keep some bio media in one of my established filters. That way I can use it as a QT tank, a hospital tank or an isolation tank. In the meantime I’m mainly concerned with how to go about returning the AquaClear 30 HOB filter to the main tank as safely as possible? The only medicine I used in the “hospital” tank was a dose of Melafix and some salt. Should I be concerned with disinfecting the AquaClear 30 filter before I put it back on the main tank or should I just give it a thorough cleaning then dose the main tank with Melafix and salt in an attempt to keep the rest of the fish healthy and kill anything remaining in the water? I don’t want to risk infecting or killing the rest of my fish but at the same time I don’t want to kill all of the BB in my filter… Anyway sorry for all of the rookie questions, this is my first experience with a sick fish and my first fish fatality. If at all possible, I’d like to keep it to just the one. Thanks in advance.

- Nick

Toss out the filter sponges in that Aquaclear 30. Get some new ones. Wash everything down in a 10% bleach solution, rinse, let dry. The Aquaclear fileters (I use 'em too) break down really well for cleaning, so take the thing all the way apart and soak everything but the motor. Clean and rinse the impeller cup really well on the motor. Clean the o-ring with soap and water, don't use bleach on it or you could find yourself with a leak. Replacing it is an option, but you'd have to troll the hardware store for a similar one.

Let everything dry, rinse one more time, and start 'er back up.

I have one of those filters too, it will be fairly easy to clean.

I don't know how many people agree with me, but I wouldn't worry about disinfecting it. The fish had a wound that got infected. The bacteria that infected the wound was and still is in your display tank. The other uninjured fish are fine, and should continue to be fine. I'd rinse everything off with hot water and put it back.

I don't know how many people agree with me, but I wouldn't worry about disinfecting it. The fish had a wound that got infected. The bacteria that infected the wound was and still is in your display tank. The other uninjured fish are fine, and should continue to be fine. I'd rinse everything off with hot water and put it back.

At least one person agrees.

I also agree with you, as that is exactly what I did.

The other 3 fish in my main tank still haven't shown any signs of injury or illness and so far they seem to be doing just fine. Since I removed the sick fish on Monday they have been acting a little more shy/timid than usual but I’m pretty sure that's because Monday was the first time I’ve ever had to stick a net in their tank. That and the 50% water change I put them through last night has definitely stressed them out. The largest water change they had seen up to this point was 25%. Anyway, all I did last night was remove the filter from the hospital tank and cleaned it and the sponges with hot water. I dropped the bag of ceramic bio material into the bucket of old tank water that was draining from the main tank. From there I emptied and cleaned the 5.5 gallon tank and stored it for future use. After that was done and the main tank was drained I put the filter back together, installed it back on the main tank and refilled the tank with new water. I did not feed the fish last night due to the stress they had been put through the past two days so they should be rather hungry when I get home today. As of this morning everything looked normal but I will be sure to give the fish and the tank a thorough examination today before I feed them. Thanks for all of the help. The only question I have now is whether or not to replace the fish I just lost. That and if I do replace him should I do it right away or should I leave the 3 of them alone for a while?

The only question about cleaning involves cross-contaminating other tanks if that's a concern you've got. I've got one tank with some very nice sunnies that has a strange bacterial infection (kinda like cottonmouth) that doesn't respond to anything I've tried. It's spread to all the sunnies in the tank, so any time it gets bad, I'll separate one or more of the most aggressive fish into a quarantine tank. All that gets cleaned well since I have multiple tanks that I really don't want this spreading to. It doesn't slow down the fish at all, even when it gets bad, but I'd rather it stay contained.

I also don't use nets in other tanks that I've used in this one, for the same reason.

As to restocking... up to you. You're going to have to go through the aggression and acclimatization whenever you do it, so just put a new fish in when you feel like it.