Telescope goldfish: a beautiful eye that sees poorly and needs careful care

I read a guide on the telescope goldfish, also called the bubble-eye, and found it useful for anyone who falls for one at the store. The telescope is a variety of the common goldfish (Carassius auratus) with eyes that stick out from the head, selected by breeders in China and Japan over centuries. The eyes usually start to bulge at around three to six months of age.

The core point of the article is that big eyes do not mean good vision. Breeding prioritized looks, and the result is a fish that sees worse than a common goldfish, bumps into decorations, and takes longer to find food. So feeding needs patience: use slow-sinking pellets instead of flakes, soak them for a minute or two before offering, and always feed in the same corner of the tank.

Another tip that caught my attention concerns tank mates. Fast fish such as common goldfish, comets and barbs eat everything before the telescope finds the first pellet, and the result can be slow malnutrition. Round-bodied, slow-swimming varieties such as ryukin, oranda and lionhead get along much better. And since goldfish are cold-water fish, they don't mix well with betta, guppies or tetras.

Decorations should be smooth and rounded, with no sharp-edged plastic plants or pointed rocks, and it's worth covering the filter intake with mesh or sponge. The guide's rule is practical: if a decoration would hurt your hand, it will hurt his eyes. If an eye gets injured, remove the cause, improve the water, and watch him for a few days.

Source: Mundo Aquário