fancy tail guppy male is wobbling, is this normal?

[Babypleco]

Hello. A friend recently gave us a pair of fancy tail guppies. The male guppy swims in a very wobbly pattern, and his tail always hangs much lower than his head. However he also has the most elaborate tail and dorsal fin I have ever seen! His dorsal fin alone is almost the length of his entire body. My friend says that the fish swims that way because of the weight of its tail and back fin, but I am wondering if it might be ill, and should I isolate it? (My friend is not knowledgeable about fish diseases, water parameters etc.) Apart from the strange swimming, the male guppy acts normal otherwise - he chases and tries to mate with the female guppy, and he feeds with the other fish. The female guppy that came with the male does not wobble or look imbalanced, it's only the male.
I have a 50-gallon established tank with guppies, mollies, a dwarf gourami and a common pleco. Temperature 80 degrees, weekly 30% water changes, ammonia and nitrite are 0, nitrates 20. All my other fish are healthy. Thanks in advance for your answers.

[bullseyejoey]

I think your friend is right. If the fins are big on guppies, the fish is weighed down by the fins.


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[C. King]

"wobbly' is kinda vague to go on, but if he's eating, and the other fish are fine, the water parameters are good, and the guppy shows no other signs of illness, I would just keep an eye on him, and hope it is normal for him.

[TheOldSalt]

Yes, I agree. This wobbly drooping is very common in guppies with very long fins.

[Babypleco]

Hi again,
Thank you all for your replies. However there has been a new development, I came home from work this evening to find the same male guppy shaking/trembling (the way someone might when they are very cold/"have the chills") he is doing this continuously. He has now been isolated to the quarantine tank. The female is still fine and so are all other fish. My fear now is that whatever this is, I hope it hasn't spread to other fish...

[bullseyejoey]

They do this I know when the water parameters are unstable. Check your water parameters


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[TheOldSalt]

Oh. That's called "shimmying."
Chills actually DO cause it, but it can take days or weeks to recover. Illness is another cause.

[Babypleco]

Wow! I decided to re-check my water parameters in the quarantine tank and the nitrites were at 10!!! (Even though I had filled the tank with water taken from my 50-gallon tank where the nitrites are still at zero!) Ammonia was still zero in both tanks and ph 7. I did a 75% water change in the quarantine tank with some extra Prime, and have added some aquarium salt as well, and my quarantined guppy has stopped shivering and wobbling. The funny thing is that he was wobbling in the main tank first, and that I have barely fed him, so I have no idea where the nitrites came from. However I am not putting him back just yet and will just test the water more frequently. Thank you again for all your answers/ suggestions, they were much appreciated!

[MrKrabs]

Breeders will often trim a male guppys' tail to look better at show. If the caudal is too big it can prevent him from easier access to mating. It does grow back slowly.

[C. King]

Originally Posted by MrKrabs Breeders will often trim a male guppys' tail to look better at show. If the caudal is too big it can prevent him from easier access to mating. It does grow back slowly.

eewwwww! that just sounds like torture and mutilation to me! gives me the heebee geebees just thinking about it.

[MrKrabs]

I trimmed my male guppy's tail by about a third. Was quick and no blood. He immediately went back to eating after returning him to his tank.

[Babypleco]

Unfortunately, the male guppy passed away yesterday. His shimmy/wobble never went away completely. The female guppy I received at the same time with him is now in isolation as well, she does not shimmy but her gills look inflamed and all her fins are frayed with some kind of brown stuff along the edges. I am not sure if its the stress of the new aquarium or if these fish were already infected before I got them. I am now seeing some of my other fish (previously healthy) starting to flash/rub against aquarium objects, so I will probably have to treat my entire tank.