Nick_593
Member
Hello everyone,
Just made some observations with the fish I have in my tank. I have 8 Cardinal tetras in my tank, and there is always just one that is much larger than the others. A few weeks ago the largest one died, and within 4 to 8 days, one of the others grew to be much bigger than the rest, very rapidly(!). Then, just one remains far larger than the rest of the Cardinals. I have seen this happen a few times over the years, and this idea popped into my head looking at my tank today.
Protogynous hermaphroditism is an alternative mating strategy which allows individuals to pass on their genes more efficiency, when there is high competition to breed between males. So in fish, it is sometimes best to start off as female (pass on genes if you cant compete with the bigger males), then change to a male when you have a better chance to compete (by becoming male you pass on even more genes than females if your able to become the biggest male in the pecking order). So in the Cardinal tetra, I am wondering if the second most dominant individual in a harem changes sex from female, to male, to basically become 'top of the pecking order', as in nature males pass on more genes than females in many cases. This is process quite common in marine fish, and some freshwater. But wondering if this applies to any tetras.
I'm wondering if anyone has noticed similar observations to me with their tetras (i.e. has anyone noticed that one of their tetras is much larger than the others in the tank- a stack contrast?)? I'd say this applies to 10 or less fish (or thereabouts!), as I don't know how big a harem would be with these fish.
Would be interesting to know other peoples observations with their tetras?
Just made some observations with the fish I have in my tank. I have 8 Cardinal tetras in my tank, and there is always just one that is much larger than the others. A few weeks ago the largest one died, and within 4 to 8 days, one of the others grew to be much bigger than the rest, very rapidly(!). Then, just one remains far larger than the rest of the Cardinals. I have seen this happen a few times over the years, and this idea popped into my head looking at my tank today.
Protogynous hermaphroditism is an alternative mating strategy which allows individuals to pass on their genes more efficiency, when there is high competition to breed between males. So in fish, it is sometimes best to start off as female (pass on genes if you cant compete with the bigger males), then change to a male when you have a better chance to compete (by becoming male you pass on even more genes than females if your able to become the biggest male in the pecking order). So in the Cardinal tetra, I am wondering if the second most dominant individual in a harem changes sex from female, to male, to basically become 'top of the pecking order', as in nature males pass on more genes than females in many cases. This is process quite common in marine fish, and some freshwater. But wondering if this applies to any tetras.
I'm wondering if anyone has noticed similar observations to me with their tetras (i.e. has anyone noticed that one of their tetras is much larger than the others in the tank- a stack contrast?)? I'd say this applies to 10 or less fish (or thereabouts!), as I don't know how big a harem would be with these fish.
Would be interesting to know other peoples observations with their tetras?