Strange Growth on Oranda-- Please help

[Franco]

I have an oriental oranda with a strange growth between its two tail fins. It is where the fins meet the tail. It looks like a dark yellow bubble/sac filled with liquid. It wiggles around when the goldie wags her tail. It doesnt appear to be harming anything but its unlike anything I've ever seen. It resembles the bubbles on bubbleeye goldfish but it is between the tail fins. Do fancy goldfish get weird growth like that because of their breeding? What should I do with it?

[OrionGirl]

Goldfish do get growths during breeding, but tubercles look like little whiskers.

Does this look like a blister? If so, I've seen something similar on a cory. I never knew what caused it, and it went away on it's own. Sorry--I can't offer more.

What are the water conditions? Temp? Tank size/mates?

[Franco]

It doesnt look like so much as a blister but a bubble. I swear to God it looks exactly like the bubble below the eye of a bubble-eye goldfish. This guy who has been selling fish for 40 years told me to pop it and it will heal on its own. But if its not hurting the fish then its kinda cool to have a "bubble butt" if you pardon the pun.

55 gallon planted community tank
Ammonia=0
Nitrite=0
Nitrate=20ppm and lowering
pH=8.5
Temp=75* when the heater has to run but usually 77-78* because thats how warm my apt is.
Tank Mates: 5 neon tetras, 1 female guppy, a 9 inch pleco, 3 albino corys, a 2 inch oriental black moor, 3 canas, 5 brigs, and a few hundred baby canas and brigs in breeder nets.
Plants: Anubias, some ludwigia, elodea, java fern, and about half a pound of duckweed that was added today as a treat (its already half gone lol).

[OrionGirl]

The temp might be part of the problem. The fancies like it warmer than the shebunkins, but still only in the lower 70's. You might look at adding a fan to blow across the surface. This will increase evaporation, but it will also cool the water a few degrees. If you run lights, try reducing the time that they're on as well.

Good for you on giving them fresh veggies! In addition to the duck weed, the goldies will appreciate slices of orange and watermelon, leafy lettuce, zucchini, etc...And so will the canas and brigs!

You should consider setting up another tank for the tetras, guppy and cories, as they really will do better at the higher temperature. Something smaller, like a 15, would be fine for them. The pleco will eventually have to go to either a much bigger tank, or a pond. There are some nice species of bottom feeders that won't get as large, and will do more actual cleaning. You'll also want to make sure the pleco isn't bugging the goldies. As they mature, they becoming increasingly omnivorous, and are well known for going after big bodied tankmates in an effort to get more protien.

[Franco]

This was never intended to be a permanent situation. I was prolly going to move the goldies to a smaller tank and use the 55 as a tropical only. I do need to find the pleco a new home but right now he is still doing a good job of cleaning--better than when he was younger.

All the fish and snails get zucchini, summer squash, and frozen peas every night. About twice a week I'll give them turnip greens and spinach but thats mostly for the snails. My oranda is the fattest goldfish I've ever seen for only being 2.5 inches long. She has a belly bigger than that of any pearlscale I've ever seen of the same size.

When I got back from class today, the yellow sac on her tail has reduced in size. It might have popped or something. Its prolly just a fatty tumor or something.

What happens when you feed goldfish only tropical fish flakes?

[OrionGirl]

Honestly? I don't know. But I'd suspect that they will start suffering from malnutrition, and possibly be more prone to ailments.

Good for you on keeping them fat and happy. And really--the goldies will do better in a bigger tank. They produce more waste than the smaller fish.

[Franco]

well I figured the goldies would do fine in a 20-30 gallon since I only have 2 of them. I could control their waste more effectively in a smaller tank I think without all the clay pots, drift wood, aquatic plants, and limestone shelves that I have in my 55. I always use filters that are rated to at least double the size of the tank. I had a 10 gallon with a 60 gallon HOB filter that still had problems but it was also grossly overstocked. I need more or bigger tanks than what I have but I'm kinda low on space.

I've been thinking about getting or making a canister filter but I don't know anyone who uses them so I'm kinda ignorant about the advantages or disadvantages that they have.

In your opinion, whats the best filtering system? I've used aquaclear HOBs, the biowheel waterevers (didnt work hardly at all), and UGFs or a combination of HOBs and UGFs. I'm really not sure of what I really need to have.

Is there a way to filter nitrates from the water or are water changes and aquatic plants supposed to be enough? I have this idea to put small willow tree saplings in the back of my HOB to act as a nitrate sponge. Apparently willow is supposed to suck up nitrates like crazy. I tried it before with just willow branches in the tank itself but the branches never sprouted roots.

[OrionGirl]

Goldies need at least 5 gallons per inch of body--and many say 10 gallons per inch is the minimum. Smaller tanks are not easier to keep stable--there's less water to dilute the pollution. I agree, less decoration makes it easier to clean the tank, but you still want to have some cover for the fish, or they'll be stressed.

Canister filters are good--and can be setup to be very good. The key is to have mechanical filtration in the intake (a simple sponge works) so the bio-media in the canister doesn't need to be disturbed for rinsing, and all the solid wastes are easily captured. Check around here--there are several people using canisters they recommend.

For me--the filter choice depends on the tank. The more stocked a tank is, the harder itsn't going to be to keep it clean no matter what hardware is used. The largest FW setup I've had are 55's, and I ran them with Aquaclears. I like the AC's because they're easy to clean and can run a variety of media, but that doesn't make them the best for everyone. I've also ran a UGF, and if I were to use it again, I'd go reverse flow--the water pushes up through the gravel, instead of pulling down through it, so solid wastes don't get trapped in the substrate as readily, requiring less gravel vaccuuming.

On nitrates--water changes and plants are the best options. In FW, you can setup a plenum, but that will involve completely tearing the tank apart, and won't work with any fish that dig around in the substrate. Water changes are best, though, since a) they remove the other pollutants that we can't test for and b) they replace elements that are used up by biological processes, which helps stabilize pH. There are plants that will grow with their roots submersed, but I can't say if the willow you have would do so. More plant mass will help--but ultimately, water changes are still a requirement for long term stability. There are a lot of high light, CO2 supplemented tanks where nitrate is added because the fish don't create enough--and in those setups, not only are nitrates added and partial water changes done, but other nutrients are supplemented as well.