Bullying and Spasms?

[JemZ]

Hello

I have a 10-gallon tank with an Algae Eater, A Molly, and A Swordtail. Recently, the swordtail has been acting really aggressive towards the molly: nipping at him, pushing up against him with his body, chasing him. The molly seems to hate it; he swims away quickly and hides in the corners. I was worried that he might get injured so I put the swordtail in a separate bucket for around 90 minutes. Once I put him back in he was much less aggressive. Today though, he was back to his old self. As of around an hour ago, I saw the molly begin to have quick, momentary spasms where he went sideways. I did a 10% water change but would like to resolve the issue before something worse happens.

 

[Essjay]

Removing a fish for a few minutes will not change its behaviour, I'm afraid.

Male livebearers will try to mate with any other fish in the tank if there are no females, and this could be what you are seeing.
But I have to tell you that 10 gallons is too small for these fish. Swordtails and mollies need a tank at least 36 inches long. Being in a tank that's too small stresses fish and some cope with this stress by becoming aggressive.

 

[JemZ]

I understand. I was actually suspicious that something along those lines was happening. I was considering returning the swordtail back to Petco or another store that would allow me to surrender fish. Is this the best option?

 

[Colin_T]

pictures and video of the fish?

 

[JemZ]

Ok, here they are. Funnily enough, whenever I would sit on the couch and watch and wait for the swordtail to be aggressive so as to get a video, he would behave himself. As soon as I went into the kitchen to get a snack, he started chasing him again as If he knew what I was doing lol

Ok so this is the swordtail who is being aggressive:

And this is the molly he is chasing:

And then here are two videos of him doing it. He has been even more aggressive than shown in these videos, but these are the ones I could get:

 

[AdoraBelle Dearheart]

Ok, here they are. Funnily enough, whenever I would sit on the couch and watch and wait for the swordtail to be aggressive so as to get a video, he would behave himself. As soon as I went into the kitchen to get a snack, he started chasing him again as If he knew what I was doing lol

Ok so this is the swordtail who is being aggressive:
View attachment 120295

And this is the molly he is chasing:
View attachment 120296

And then here are two videos of him doing it. He has been even more aggressive than shown in these videos, but these are the ones I could get:

That molly is a female

 

[AdoraBelle Dearheart]

That molly is a female

Scratch that, I think that molly is actually a female platy, and it looks gravid.

How long have you had these fish?

 

[Essjay]

That would also explain the chasing - he is trying to mate with the female platy. Swordtails and platies can interbreed, in fact a lot of swordtails sold commercially are already swordtail-platy hybrids.
Males of all the common livebearers have one track minds, which is why it is always recommended to have more females than males, so each female gets time off while the males chase another. But 10 gallons is too small for multiple females - and the fry they will have every month.

 

[AdoraBelle Dearheart]

The tank layout is also a problem, even if the fish were smaller species like guppies and all males, it's very open, no where to hide, no breaks in lines of sight. More planting and decor with the right numbers of fish reduces the chances of one fish harassing another.

In one of those videos, you see the swordtail swim next to her and shimmy his tail? He was displaying to her. It's a courtship ritual, not bullying. But, male livebearers being what they are, and with only the two of them in there, they can harass constantly until the female is stressed and exhausted to the point of killing her. It's urgent to fix this, and the tank is too small for swordtails or platies. Especially a female platy who looks a week or two away from dropping fry, there isn't space here to keep a breeding female, you'll be over run with fry, if the males harassment doesn't kill her first.

You'd do better to return both these fish (and please post a photo of the algae eater too, that could mean a few different species of fish) and going back to the drawing board. Researching what species of fish can go in a ten gallon tank, what your water conditions are, and which fish you can keep for their entire lifespan in that tank. We'd be happy to give you more advice if wanted.

 

[JemZ]

Wow, thanks for the great info. I didn't even know it was a she. I don't think she's pregnant though, she's had the large belly ever since I got her, which is why I thought she was a balloon-belly molly or something similar. Here is a picture of the algae eater. He never bothers anyone except on the occasions where they get too close to the house he sits in for most of the day. He's still recovering from what I think was a parasitic infection he had.

 

[AdoraBelle Dearheart]

Wow, thanks for the great info. I didn't even know it was a she. I don't think she's pregnant though, she's had the large belly ever since I got her, which is why I thought she was a balloon-belly molly or something similar. Here is a picture of the algae eater. He never bothers anyone except on the occasions where they get too close to the house he sits in for most of the day. He's still recovering from what I think was a parasitic infection he had.View attachment 120327 View attachment 120328

Oh no, I think that's a Chinese algae eater. They get big, and mean, if it is one. Also not suitable for a ten gallon. @Wills @Naughts do you guys have a better idea for an ID?

 

[Wills]

Yeah Chinese Algae Eater - potentially grows upto 10-12 inches long, though usually about 8.

 

[AdoraBelle Dearheart]

Wow, thanks for the great info. I didn't even know it was a she. I don't think she's pregnant though, she's had the large belly ever since I got her, which is why I thought she was a balloon-belly molly or something similar. Here is a picture of the algae eater. He never bothers anyone except on the occasions where they get too close to the house he sits in for most of the day. He's still recovering from what I think was a parasitic infection he had.View attachment 120327 View attachment 120328

It definitely isn't a balloon belly platy, the head shape is normal, and the top of the head looks deformed in the balloon bellies, yours doesn't have that. Definitely female, she has the fan shaped anal fin, and I'd bet real money that she's gravid. I can see the shape of the eggs in her belly, and that silvery sheen on her sides is a giveaway too. It's very possible that she's either had fry before that were eaten before you saw them, given that they'd have no where to hide, or she reabsorbed the first batches and she's gravid again. Stress and not having a suitable place to birth can make them reabsorb. Female livebearers can store sperm for a year or more so even if the male swordtail didn't mate her successfully, she could be carrying platy sperm and continue to fertilise her own eggs even with no males around. Female livebearers even if bought from female only tanks are often already carrying sperm I'm afraid. It only takes one male to jump into the female tank either at the farm or at the store, or if the batch of fry she was born into isn't divided into sexes early enough.

 

[JemZ]

I feel kinda bad now because I wasn't aware that all of this stuff was happening. I never really knew much about fish until I joined this forum and am now learning a lot. The reason for my poor aquarium choices is that I never really researched before getting a tank and getting new fish, instead just went into the store, bought a tank, and some fish. I am learning though. I take responsibility for not doing more research and will definitely do more in the future. But I'm happier now that I know what is happening, and would prefer the guilt I have to not knowing and assuming everything is going great. Now that my emotional confession is over, I think it is time for me to make some decisions. I obviously would hate to get rid of any fish, but I do want what's best for them so I probably will return the platy and swordtail. I wouldn't mind keeping the algae eater, but I assume if I were to do that I wouldn't be able to get much more fish if any at all due to his size and future character. I'll also look into more suitable fish for a 10 gallon. Since I'm not able to return them at the moment, is there any way I can help the situation until I am able to return them?

 

[Tez_20]

David i brought some of these and the aggression can be terrible and that was towards my other fish so i took them back to shop, as he as a large quarantine bay for taking in fish.