I have a small in greenhouse pond with a red-headed slider and 3 goldfish. The turle is about 20 years old and
the goldfish have been his companions for the last about 15 years. No he has never bothered to eat them - I think he's too chubby and slow but also think his eye sight isn't the best.

My problem: over the last year, all 3 fish have grown tumors all over their bodies and died, the last one today.

My question: If I clean the filter so getting rid of any lingering problems, do you think I can add more fish? Or is the turtle giving them some disease that's taken all these years to manifest itself? Or maybe.... ? There was a tiny-sized snail infestation but between the fish and the filter, I think they're gone.

to the site and to the forum!

Turtles are omnivores, so they eat all sorts of things, including fish. If your turtle were to give you a problem, it would be in the form of fish skeletons. I don't think your turtle is the problem. Our turtles over here (Western Painted) do just fine with the fish in lakes, ponds, and streams (obviously excluding the fact that they will eat each other, with the fish eating the turtles' young, and the turtles eating the smaller fish).

And if the turtle had a disease it was spreading to the fish, the turtle itself would most likely be having problems. I think there's something else going on here. I think cleaning out your filter is your best option right now…if you still have a problem, we'll take try to figure it out from there.

ETA: Is it possible that maybe the fish just died from old age? Although I don't know if fish get tumors when they die from old age…

Do you have a quality u.v. Filter for your pond? Does the water circulate through it?
It could be a parasite that has invaded your pond and the U.V. Would help with that. I had one on my pond for many years.
They also make a liquid tonic that you could use to promote the over all health of your fish. I used it twice a year, Spring and Fall.

The average lifespan of a pond-raised goldfish is 12 years. Your have lived beyond this date so you did nothing wrong.

Unfortunately fish, very much like all organisms, become far more susceptible to sickness as they age, so if those goldfish were all 15 year old and perhaps genetically closely related there's no need to beat yourself (or the terrapin) over it. They lived longer than average.
Get some new goldfish... assuming you haven't got herons. They are by far the first cause of death for pond fish around here.

Oh gee, I didn't catch on right away that you had snails in your pond. that could be causing your problem! In my reading back in the mid 80's, regarding ponds and fish, snails were not something that the pond needs. They are known to carry several parasites that are harmful for fish.

I had a 8' x 14' by 30" deep pond in my backyard on Long Island as my kids were growing up. That was about 1,600 gallons. It had a biological filter with internals sponges and material which were colonized by millions of beneficial bacteria to help clean up fish waste and such. I never cleaned that filter 100% spotless because I wanted enough of the beneficial bacteria to remain behind to help clean my water. The UV filter that I mentioned was to control algae and parasites in the water. That required a rather pricey new bulb every year in order to keep those bad things under control.
But when my fish awoke every spring from their winter rest, I would add a tonic to help them build their natural immunities back up. I would use it again in the fall. AND eve then, 'FISH POX" was an occasional problem. That had to be treated as it occurred. I would net the fish if possible and dab on some chemical whose name escapes me at the moment. But it cleared up the pox in a few weeks. Do Not overfeed the fish!! Wasted food sitting on the bottom of a pond is not a good idea either. I thought of the pond as an ecosystem, the cleaner I kept it, the healthier that the fish were.
Pond keeping is an ongoing thing. Nothing is ever easy. Sometimes the smaller the pond, the more problems you have.

It's an indoor pond. The tiny snails were introduced with a plant added for "vegetables". I do know those tiny snails do carry diseases but I think the snails are all gone now. Now veggies are chard and lettuce leaves. I do have outdoor ponds and have never had snail or algae problems in them. The turtle eats the inside algae when it grows. No herons but raccoons are a problem. We always used ground level hot wires to keep the herons out (when I lived in an area with a heron problem).

My big concern now is if the diseased fish are gone and the snails are gone, is the water "clean"?

You didn't answer my question yet I don't think. UV filter?

Just because snails might be gone or not seen, does not mean that potential problems are gone.

No uv filter, just a big Fluval. I dont think I'll get a uv filter either as the pond is in a rainforest.

I have never fed my fish.

Well, I can't add anything more.

It does seem pretty coincidental that they've all died in such a short span, but if they were about the same age (which I assume they were), it doesn't seem unexpected to me.

There are some fish diseases that stay in the water, but I think most, if not all, die without a host. It's hard to say what could have caused the growths (could of been cancer from old age or it could have been from something like fish TB--- which is transferrable to humans). Short of a fish vet or something obvious like popeye, it's hard to tell sometimes what ails them or how to fix it.

I don't know a lot about fish diseases and if they're transferrable to a turtle or if a turtle is capable of transferring something to a fish. But, assuming it was something from the snails (also assuming the turtle didn't contract it too), I think without a host, whatever it could be, will die.

Just curious. When you say clean filter, do you mean just squeezing it out in dirty water or replacing it altogether?

If it were me, I'd give it a good month with just the turtle in there and then try new goldfish. God forbid I'm wrong, but I think that if there's anything that could affect a new goldfish in there, in a month's time, it'll be dead (again, assuming it isn't something your turtle can also contract).

Sorry for the rambling, but I hope this helps.

Also,

It's a Fluval canister filter. I run the sponges through the wash machine (without the soap) a couple times and rinse all the ceramic beads.

The fish tumors were more like blisters (I broke one once, it drained, didnt kill the fish but more grew). One by one, all 3 fish got the "uglies" but it didnt seem to affect their health. It's all very strange. Whatever it is, the turtle isn't affected.

Oooh. I'm kind of surprised that doesn't ruin your cycle (are ponds "cycled"?).

That does sound odd. It doesn't sound like a tumor to me, almost more like an abscess? Did it have pus, blood, etc in it?

That is really strange. I'm not even sure what that could have been. :sad:

But, hopefully, giving your pond some time with just the turtle will kill the cause off.

Or it could be Hikui. Hikui is treatable with a specific medication, Fish pox has no treatment.
It can lie dormant in fish for a very long period of time. Then all of a sudden it can appear causing redness or discoloration of skin. Can cause raised welts or lesions. I could not find any direct correlation between Fish pox and turtles but it is possible I suppose that a turtle could be a carrier. It may never harm the turtle at all.

But since my limited research indicates long term inactivity and no known cure, I would break the whole pond down and completely sterilize it. Euthanize the turtle.

Or move the turtle. Or, not get more goldfish.

I've had the turtle for 20+ years - it's his pond. The fish are for glitz.

Suzume said: It's an indoor pond. The tiny snails were introduced with a plant added for "vegetables". I do know those tiny snails do carry diseases but I think the snails are all gone now. Now veggies are chard and lettuce leaves. I do have outdoor ponds and have never had snail or algae problems in them. The turtle eats the inside algae when it grows. No herons but raccoons are a problem. We always used ground level hot wires to keep the herons out (when I lived in an area with a heron problem).

My big concern now is if the diseased fish are gone and the snails are gone, is the water "clean"?

Replace the water in the pond and clean the sludge at the bottom (put it in the compost pile, it's good stuff): it's something that should be done once in a while with any small pond even if you have a very good filtration system. It will take care of any pathogen you may conceivable have and you sill be able tosee if any "alien" is present.

There's no sludge in the bottom. It's a very clean pond. All the sludge is in the filter canister - I use it to water plants. I'll try to take a photo.

I'd go buy some inexpensive gold fish and put them in, sometimes you can find people selling/giving away goldfish like on craigs list. If you buy feeder ones Mr Turtle may eat them You can also put minnows in there as a test or to just keep skeeters out, the turtle may eat those too but if you provide places for them to hide and buy a dozen or so to begin w they breed quickly. It is very unlikely your turtle caused this. Goldfish get tumors sometimes, I've had them do that too. I would not break down the pond and scrub it all out, you will lose all the bacteria and so forth, will turn into a mess. There is no need to kill your turtle, he did not cause this. When you buy new fish, put them in a tank for 2 weeks and watch to make sure they don't have anything wrong with them that needs treated (ich ect) then add them to the pond. If you are getting goldfish from an already established pond-all the same place, you won't need to do this. Be careful treating fish IN the pond as the meds may harm your turtle.

Killinh the Turtle (his name is Spot)was never an option.
He's the pet, not the fish.

Here's a photo.

Oh, he's cute.