My female Betta looks fat. Is she pregnant or ready to lay eggs?

Beta fish lay eggs and she would need a male to then fertilize those eggs after she lays them. Breeding betas can be very work intensive. Here is a link with great information: fishkeepingworld.com/breeding-betta-fish/ As the babies get bigger, they can graduate to larger food. The babies will mature and need to be separated around 3 months of age. The females can stay together but all the males will need to be separated. Breeding betas requires a lot of tanks/space. I recommend to connect with a local aquarium store and find out if anyone has first hand knowledge. I hope this helps and please feel free to post any additional questions.

A female guppy will develop what is known as a "gravid spot" when pregnant. It is triangular and located near the vent on the abdomen under the tail. It will get bigger and darker as she nears spawning. If she was skinny when you got her and she is that big now, she is pregnant. They are live bearers, so the fry (baby fish) will need cover (places to hide) or they will be eaten. It is best to separate them into grow out tanks.

Thanks for reaching out and including photos. Coeloms (abdomens) are swollen, but unable to determine if eggs. Often when it is time to spawn, the vent becomes slightly everted. An ultrasound would be the only way to truly determine if eggs are in the abdomen. Good luck.

You need only provide plenty of space, clean water and a quality flake or pelleted diet. Male goldfish will develop white dots on the fins and gills when ready to mate. He (they) may chase her around and bump her stomach to get her to spawn (lay eggs). When she is ready, she will seek out planted or quiet area of the tank and spawn. The males will then release sperm to fertilize the eggs. The eggs will need to be removed to a separate tank to prevent them from being eaten by the adults. The eggs will need to be kept at a certain temperature and in clean water until they hatch within a week's time. Afterwards, you will have MANY fish to care for and feed. This can quickly become an overwhelming task and should not be undertaken without serious forethought. You can read more about goldfish breeding here: http://thegoldfishtank.com/goldfish-care/breeding/goldfish-breeding-breed-goldfish/

Thanks for providing pictures. Through the pictures, there is a good probability that your fish are gravid and should deliver soon. Hard to tell what species by the pictures (slightly out of focus), but usually with dropsy, the scales rise (pineconing) and the swelling extends more caudally. Dropsy is more a clinical sign and not a disease. Causes include heart, renal, liver or gonadal diseases. There is no one treatment, but depends on the cause. Few are successfully treated, unless a bacterial infection and the proper antibiotics. Hopefully you will have eggs or babies in the next few days.

If you also have a male in the tank, it is very likely that she is at the beginning of pregnancy. Keep watching her and the black spot should be getting bigger and she should be getting rounder. This is a live-bearing fish, so make sure there are a lot of plants somewhere in the tank, so the babies can hide from the parents, as they will eat them.

Not necessarily unfortunately. Abdominal infections, skin oedema, overinflated swimbladder can be common differentials. A check up is required to understand underlying condition and treat appropriately (if treatment is needed). Hope this answer was helpful, but please do not hesitate to contact us again on the forum or by requesting a consultation if you have any more questions or to discuss it any further.