Do Spanish dancer nudibranchs eat flatworms? How to control them?

Planaria are notoriously difficult to completely remove from an aquarium. You can perform a thorough vacuuming of the gravel or substrate followed by a 30% water change every few days. Use only conditioned water that is temperature matched to prevent stress or shock to tank inhabitants. Fenbendazole or praziquantel can also be used during this process. Since you are overseas, you can also look for a product called "Planaria Zero" that is supposed to be quite effective. It contains extract of betel nut which is toxic to planaria. Use caution with any medications if you have snails or shrimp in the tank.

The best method to keep detritus worms in check is to perform regular tank maintenance. this includes regular partial water changes, vacuuming the substrate regularly, removing dead plant matter and not overfeeding. Detritus worms are a normal part of the tank ecosystem and play a large role as the "clean up crew". They will not harm fish. You can treat an overpopulation with praziquantel. Find it in the aquarium section of the local pet store. Follow label directions carefully and monitor for an ammonia spike from decaying worms. You will likely need to clean the tank (as described above) after treatment to stabilize chemistry and/or to improve water quality. Using this treatment does not mean you can skip out on regular tank maintenance.

Thanks for reaching out about your aquarium. Fenbendazole can be dangerous to use. The likely worms are not parasitic but commensals living in the detritus of the substrate. When doing water changes, try vacuuming the gravel/bottom, as this is likely where the eggs are hatching. Try controlling in this manner prior to adding chemicals/drugs. Adding some snails or fish that will feed on the worms might also aid in control. Good luck.

Thanks for reaching out. These appear to be Camallanus worms which are not parasitic but feed on detritus in the tank. Probably brought in by a live plant or invertebrate. Check water quality and correct any concerns. Siphoning the substrate might help decrease worm numbers. If additional concerns, a veterinary visit might be needed. Good luck.

It is quite possible the eggs are infected. This can be a difficult parasite to treat. It is reportedly resistant to most wormers. Levimasole may be your best bet. To be safe, the eggs may need to be removed, dried out on paper then discarded in the trash. Do not flush them or wash them down the drain. The same should be done with fish that die or are humanely euthanized.

I can't blame you for not wanting to pick up the worms on your carpet, but unfortunately, that's the only way to get the job done. Consider putting on disposable gloves or using tongs to pick them up to dispose of them in the trash. I can't clearly see the worms in the picture that you've posted to determine which type of worms (roundworms, tapeworms, hookworms, etc.) that you are seeing. Roundworms resemble spaghetti, tapeworms resemble grains of rice, and hookworms look like longer, flat noodles with an "o" shaped mouth. Since Chance obviously has worms, be sure that he has been dewormed recently. Pyrantel pamoate ( http://www.drsfostersmith.com/product/prod_display.cfm?pcatid=1430 ) can be used to treat both roundworms and hookworms, and praziquantel ( http://www.drsfostersmith.com/product/prod_display.cfm?pcatid=35693 ) can be used to treat tapeworms. Try to disinfect your carpet as well as possible (bleach would be ideal, but would obviously ruin your carpet) with a steam cleaner to kill any eggs that may be left behind, because Chance could become reinfected depending on the parasite present. I hope that all goes well!

Sorry for the problems. Intestinal parasitism can affect small fish. Please check water quality to ensure ammonia, pH, nitrates and nitrites are appropriate. Taking a fish to a veterinarian for identification of the parasite can lead to a treatment plan for the adults. Sometimes invertebrates (snails) are intermediate host for the parasites, and removing them can reduce the problem. Good luck.