My fishies may or may not be sick...

[ThatOneGuy]

Hey everyone, I've been lurking for a bit trying to soak up the knowledge of everyone here but my fishies have me confused. I have some goldfish in one tank and some rosy red minnows in the other. All came from the same Wal-Mart feeder stock as my wife cleaned the tanks while I was out of town a month or two ago so we wanted to start light after she killed everything. So, the problems. On one or two goldfish and one of my minnows, there's black splotches. The fish seem healthy enough and the black is purely cosmetic. I really thought on the goldfish that it was just their type as the black was mostly on the body but a few of them had little Hitler-like mustaches and whatnot. The thing that has me confused is that one of the rosy red's has the black splotch as well so I'm wondering if it's some sort of fungus or something. The second issue is one of my minnows has developed a little white triangle on his forehead that doesn't quite look like any of the breeding pictures I've seen. I went searching around to try to compare it but it just doesn't resemble anything. The pictures here are pretty rough as chasing minnows for pictures is an oft-failing adventure. Either way, any ideas?

The black spots





and the triangle (triangle doesn't show as much in pics as real life. Fairly prominent in person)





Any input is greatly appreciated.

 

[Somervell]

Black on goldfish (actually any fish) can be a sign of healing tissue from ammonia burn. If the fish had been kept in feeder tanks, I rather doubt that close attention to water parameters was kept. That looks like it might be the case on your white minnow, although I would keep a close eye on it to make sure that there is no redness indicating a secondary infection. It's generally a sign that tissue is healing from damage rather than actual damage itself. Just keep a check on the parameters to make sure that you don't have any spikes occurring in your own tank.

Also, feeder fish tend to be more prone to diseases as they are bred and kept in more crowded conditions than other fish. That's one reason why people tend to prefer to breed their own feeders if possible. This doesn't mean that they can't be perfectly good pets. You just need to be extra cautious in watching for diseases and parasites.

The black spots on the goldfish appear to be natural coloration, although they could also be healing tissue. Black is a very unstable color on multicolored goldfish. Often, it will turn to gold or even revert to white on adults.

I am not a goldfish expert, but I hope that this will help a little.

 

[GoldLenny]

The technical term for a common black spot issue with goldfish (and possibly other fish but I haven't read enough about all other fish and this issue) is melanophore migration. You can google those two words to read more about this issue. As somervell said, it's usually a benign condition where the black pigmentation cells migrate to an injured area and has to do with the healing process. It's often associated goldfish subjected to high ammonia levels but I've also seen it show up on the fins of goldfish that had fin rot and as the fins grew back, they got melanophore migration as well.

That said, there is also a parasite that can cause black spot disease.

Scroll down about 1/2 way on this page for some basic info about this disease.
http://www.fish.state.pa.us/images/pages/qa/fish/worms.htm

SNIP - The black spots are caused by pigment that the fish deposits around the larval stage of a parasitic digenetic trematode, usually a Neascus spp (END SNIP)

As you can see, it's likely the same melanophore migration that forms the black spots around this parasite also...

Here's the rest of the info from the above link.

Black spots
Black spot disease is commonly observed in rock bass and other sunfish, bass, pike, perch, minnows, and other fish species. It can be identified by the presence of small black spots, usually about the size of a pin head, in the skin, the fins, the musculature, and the mouth of the fish. The black spots are caused by pigment that the fish deposits around the larval stage of a parasitic digenetic trematode, usually a Neascus spp.
The lifecycle of the "black spot" parasite is complex. The adult parasite is found in a fish eating bird, the kingfisher. The larval parasite is transferred from the infected fish to the bird during the feeding process. In the kingfisher, the larval stage develops into an adult parasite. The adult parasite in the intestine of the bird produces eggs that are eventually deposited in the water. There the eggs mature, hatch, and develop into the miracidium stage of the parasite. The miracidium infects a snail. In the snail, the miracidium develops into the cercaria life stage. The cercaria leaves the snail and actively penetrates a host fish. In the fish, the parasite becomes encysted. In about 22 days, black spots form around the cyst. This entire lifecycle takes at least 112 days to complete.
In general, the presence of the "black spot" parasite does not affect the growth or the longevity of the infected fish; however massive infections in young fish may cause fish mortality. The parasite is incapable of infecting humans and, as is the case with all fish parasites, it is destroyed by thorough cooking. When fish are heavily infected, some anglers prefer to remove the skin to improve the appearance of the cooked fish.
(END SNIP)

The Skeptical Aquarist has a good article about trematodes. They seem to be benign while in the encysted phase which is why your fish don't seem to be showing any kind of problems. Just keep an eye on them and read the articles.
http://www.skepticalaquarist.com/docs/health/trematodes.shtml

 

[ThatOneGuy]

Well, it sounds like the good news is that whichever is the case, neither is contageous and the ultimate question is just whether or not THAT fish makes it though the odds seem very high. It doesn't appear to be any more risk to himself or others. I'll be sure to keep an eye on it and keep the water healthy but hopefully it'll take care of itself.

Oh, and I've suspected it of spreading but it was just a gut feeling as I didn't really have any way to prove it. Those fish are only a week or two in my tanks so it could make sense that it were an amonia burn heal in progress.

Thanks for the input, it is greatly appreciated and highly relieving.

 

[GoldLenny]

Now, all that said, make sure you have a BIG tank for your goldfish. 30G per fancy goldfish and as the fish grow, you'll still be doing LOTS of tank maintenance. 75G per long bodied goldfish... usually much better off in a decent sized pond.

 

[ThatOneGuy]

Well right now they're small and I will happily jump on any opportunity to get rid of them as they get bigger. The wife equates fish tank with goldfish so they're mostly to appease her so my fishtanks get what I want. I still have a grudge against a fish or two of hers though for killing some fish when we first got them so if I could end up with a fish eater before it's too late, I'd settle that little grudge without a problem.

Either way, they definitely wont be in that tank any longer than necessary. If size is the first justification/opportunity to move them on, I can accept that.