How can you tell if a fish is mating or is pregnant?

[Rachel'C (:]

I have got two fish. They are coldwater and i just keep them in a fish bowl in my room. Lately though one of them keeps following the other and is sucking near its tail. Is this mating? Also,my fish has rapidly increased my size? Is this a sign It's pregnant. I don't know the sex coz its impossible to tell.

 

[catx]

What species of fish are they? Regardless, it's unlikely they'll breed in a bowl. Fish need proper fish tanks (or ponds in the case of Goldfish) to breed.

It could be that one of them is gravid if it's an egg layer, or its got another internal disorder that's resulted in bloating and the other fish is simply bullying it.

It would help to know what species of fish you have. All fish need to be in proper tanks with filters though, nothing thrives in a bowl.

 

[anna b]

probably so and theirs a good chance she is