Why is my glowlight tetra nipping my female betta's tail? What to do?

Thanks for reaching out about Gummy. Not sure of biting the tail is normal, especially if chewing to the point of removing part of the tail. Itching or irritation are most likely. Test and correct water quality including pH, ammonia, nitrite and nitrates. These can be dermal irritants. Bacterial or parasitic concerns, spinal problems (scoliosis due to vitamin C deficiency) are also common and a veterinary visit would be needed to assess and provide a diagnostic/treatment plan. Good luck.

Betta are definitively very territorial and you may notice multiple fights for space at the beginning. Definitively the aquarium must have multiple spots for hiding like Terra Cotta Flowerpots and PVC Piping, moss or bushy plants, ornaments, rocks and driftwoods. This will avoid open fights and will provide good places to have some rest.

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.

A male Betta can be kept in a 10 gallon tank with 5-6 neon tetras. You will need to monitor for any aggression initially as well as for any fin nipping. Male Bettas are easy to distinguish from females by their brighter colors and larger fins.

Unfortunately, aggression between species of fish is not uncommon. I am not sure if this is a new finding, or if anything has changed in the dynamic in your school of fish (any new introductions or any deaths of fish), but this often can then change how the rest of the fish interact with one another. You can try to give the platy places to hide and escape from the guppy, or you can end up dividing the tank. If you do not want to add dividers, you can also separate the guppy into another tank as well. I hope that gives you a place to start, and good luck!

Hello, Sometimes fish can lose scales from minor trauma, in which case it may be fine. However, if Mr. Nugget lost his scale from an infectious disease or internal health problem, this could be the beginning of illness. I'd recommend checking his water parameters and ensuring his environment is ideal as the first step for any sick fish. I hope this is helpful. Thanks for using Petco Pet Education Center, formerly Petcoach.

If it is an inappropriate medication, then it may cause more harm than good. Fin nipping can be caused by having too small a tank or incorrect ratio of males to females to name a couple reasons. Consider separating the one being nipped to give it opportunity to heal. Maintain pristine water quality to aid in recovery. Minor damage will heal on its own. Moderate or severe damage may require antibiotics to treat or prevent infection.