What's wrong with my swordtails?

[nosidam]

I have had three swordtails (2 female, 1 male) for about 6 months now. Everything was fine in the tank, and they seems quite active. Both females had fry, but only one survived (I wasn't trying to breed them) and is now about 3 inches long, and is fine.

About three weeks ago one of the females didn't eat dinner and just sort of stayed near the surface. I didn't think too much of it at the time, but the next day, she did the same thing at breakfast. I spent a long time looking her over and could not find anything obvious that was wrong (no ich, velvet, worms, missing scales, etc.). She was a pineapple color and it was hard to see anything due to her rather dark color.

I started treating the tank with Melafix as a precaution mostly because all of the other fish seemed fine and not exhibiting any symptoms/signs of disease.

She continued not to eat for the next 3 days. During this time, I noticed a change in her body. It can best be described as having a perfectly straight underside from front to back, with a much larger rounding of her body on the top. She sort of took the shape of a small arch.

She died about a week after she stopped eating. I examined her body very carefully, but could not find any signs of disease. I assumed it was something internal that took her.

That was two weeks ago, and everything in the tank has been fine since.

Last night, I noticed that the remaining original female is now showing the same symptoms. She is spending all her time on the bottom of the tank, under a piece of slate that is propped up against a rock. She has the same "arch" shape, and is not eating. She has some fin rot on her right pectoral fin, but the other fins look good. Because she is a marigold, I am able to see that there are some black dots on either side of her body, that I do not think were there before. These dots sort of look like the pattern of black dots that she has always had just behind her head on the top of her body.

I fear that it may be too late to save her, but I'd like to know what these black dots are, and how to deal with them before I lose any more fish.

All the other fish seem fine, and I can not see any black dots on them.

I wish I could post a picture of her, but she won't come out from under the rock.

Water quality looks good. I do 20% change every three-four days.
pH = 6.4 (little low, but stable)
Nitrate = 0-5
Nitrite = 0
Ammonia = 0

Any ideas on what's going on?

TIA.

-josh

 

[Fishman_2000]

I have two ideas on the arch shape. In one of my books they say the arch shape is a vitamin deficiency. But I think old age could have a roll to play in it too. I had a mollie who gave birth twice get the same thing and she died. I'm not sure how long mollies live for but I had her half a year and she was a full sized adult. What do you feed your fish? Here is some info that might help on the black spots. Good luck.



Symptoms:

Your fish will have small black spots measuring about 2 millimeters in diameter. These can be found anywhere on the fish’s body and fins. Cysts may be found in the internal organs. It is typical for African Cichlids, however, to constantly have little black spots, especially around their mouths. These black spots should not be mistaken for "Black Spot." These are scabs, which have resulted from digging in the gravel or from fighting.



Cause:

Larvae of parasitic digenetic flukes, Cercaria and Metacercaria. The spots seen contain larval stages of digenetic flukes. The life cycle of these parasitic flukes begins when fish-eating birds and other animals ingest fish infected with the parasites. Once ingested the parasites mature in the intestines of the host animal where they produce eggs. The eggs are then deposited into the water where they hatch and infect the livers of aquatic snails. The parasites then develop into a second and then third larval stage before leaving the snail to seek out a fish host. This type of parasitic infestation is most common in wild caught fish and pond fish.



Treatment:

Remove all snails from the aquarium or pond to end the cycle of infection. Treatment is rarely necessary and can be difficult if not impossible. Minor infestations may clear without treatment as the larvae will eventually die and be absorbed by the host's immune responses. Copper Sulfate may be helpful in severe cases.

 

[nosidam]

Thanks for the reply. She died on Sunday afternoon.

I did some research on the black spots, and my guess is that they were a symptom of a weakened immune system that was caused by whatever did her in.

I guess that all of the parasidic symptoms she was displaying (fin rot & columnaris) could have also been related to a weakened immune system.

The thing that really concerns me is the body shape change and how quickly she deteriorated.

I guess it could have been old age, but I only had her for 7 months (don't know how old she was overall). She was fully grown when I purchased her.

-josh

 

[Swiss]

Nosidam, I've had two swordtails die like that so far. Same symptoms as you described - getting more and more of an arched body shape, mope either on the bottom or top of the tank and stop eating. Never found out what was the matter, no external signs of any illness, and all other fish ok...go figure! Just to let you know your problem was not unique.

 

[tetra girl]

my tetras have small black spots on their bodies, i tried some ich med but that didnt work and it seems to be getting worse! one lemons tail is now starting to rip apart from it! Could this be the same infections? their spines are fine and none have died yet and they arent wild either.