Why is my male guppy picking on my red platy? How can I stop it?

Chances are if your female platy was kept in an aquarium with male platys the likelihood of her being pregnant is very high. The general rule for keeping both male & female live-bearers in the same tank is a ratio of 2-4 females per male. The reason for this (which you seem to be experiencing) is that the male will become very persistent and chase the females around. Keeping more than 1 female will help alleviate some stress in your aquarium. Both the male and female platy will try to eat the young fry once they are born so you may want to confine the female to a “floating nursery” until they are born. Once the fry are born, remove the female and place her back in the aquarium. From there you can keep the fry in nursery (or move them to another aquarium) until they are large enough not to be eaten.

If the Betta is not acting aggresively, there is no need to remove him. Guppies, especially males, will fight with one another but it usually isn't serious. Providing plenty of cover for them to hide may be all you need. If the fighting persists, remove the aggressive guppy to his own tank.

You can try to provide more hiding areas for your goldfish, and this may allow for it to escape from the pleco. If this doesn't work, you may need to add a barrier into the tank in order to separate the two of them. Barriers can be purchased at your local pet store, and come in a variety of shapes and sizes depending on the type/size of tank that you have. If you are able to gather information on the dimensions of your tank (gallons, length, width, and height) and take that information with you, it may be helpful for the pet store employees. If this is a recent change, you may also see if your pleco is thin - sometimes fish will become aggressive if they are hungry. You can get a general idea of the body condition of your fish by looking at their heads in comparison to their body size - if the head looks too large for the body, that can be an indicator that they are thin. Another way to tell is by looking at the belly - if it looks sunken, that is another indicator that the fish is thin. You may be able to take photos into your pet store to see if the fish are thin, or you can post another question with photos here and we can take a look as well. If you would like to discuss things further, I would be happy to do a consultation with you as well. I hope that gives you a place to start, and good luck!

Platys and guppies are usually both pretty docile, but sometimes it is the behavior of the individual Fish. Make sure there are plants for hiding and I would give it a try. Thank you for using Pet Coach.

I assume it is a male Beta? They typically are very aggressive and will kill other Fish. You could try to put a divider in the tank to keep them separate. I have seen those at most pet stores. Best of luck and thank you for using Pet Coach.

Dwarf gouramis can be very territorial. If your tank is not big enough, one will chase the other. Removing one fish or transfer to a larger tank may be necessary. You can determine sex by looking at the dorsal fin. The male's dorsal fin is pointed, while the female's is rounded or curved.

Check the water chemistry and water temperature. If it is a new tank, it may not be properly cycled and could be undergoing and ammonia or nitrite spike. Either can drive fish to the surface or to one area of the tank. Submit a water sample for testing or use a liquid master test kit at home. Aim for 0 ppm ammonia and nitrites with nitrates at 40 ppm or less. Water temp should be in the mid 70s F. Perform a partial water change (30%) if necessary to stabilize chemistry and maintain water quality. Use only aged or conditioned water that is temperature matched o prevent stress or shock. Survey the area around the tank to rule out negative stimuli such as bright/direct light or loud noises/vibrations. These can also stress fish and cause them to move as far away as possible. Make sure the tank is large enough to support 8 guppies. Overcrowding can cause stress and aggression. Lastly, provide plenty of cover in the form of live or artificial plants. Guppies prefer cover and guppy fry (babies) need it or they will get eaten.