Which drug is NOT approved for use in fish according to the provided text?

Ciprofloxacin is not approved for use in fish according to regulations surrounding veterinary drugs for aquatic species. While other options like Florfenicol, Chloramine-T, and Sulfadimethoxine-ormetoprim have established uses in aquaculture and have been approved for treating various bacterial infections and parasitic diseases in fish, ciprofloxacin does not hold the same approval status.

It is important to note that the lack of approval for ciprofloxacin could be due to factors such as effectiveness for fish species, potential impact on fish welfare, or concerns related to drug residues and their effect on human consumers. Regulations often prioritize the safety and effectiveness of medications in aquaculture settings, leading to a careful selection of approved substances to ensure both aquatic animal health and food safety for humans.