Can Fish eat ...?
Food safety index

Peanuts are not acutely toxic to fish, but they pose meaningful practical risks — including mold contamination, high fat content, and ingredients in processed forms that can harm aquatic animals. Plain, unsalted, aflatoxin-free peanuts in tiny quantities are unlikely to cause immediate harm, but they offer no nutritional benefit suited to fish and should generally be avoided in favor of species-appropriate foods. Aquarists should treat peanuts as a food of caution rather than a safe dietary staple.

Fresh pear flesh is safe for most aquarium and pond fish in small quantities, provided the core, seeds, and skin are removed first. Pear seeds contain amygdalin, a cyanogenic glycoside, but the real concern for fish is water quality rather than direct toxicity. Overfeeding any soft fruit can foul the tank rapidly, so moderation and prompt removal of uneaten pieces are essential.

Shelled, cooked peas are a safe and useful food for many aquarium fish. They are a classic home remedy for constipation and swim-bladder issues in goldfish and bettas.