Fat f ish had its chips? Add peas!

QUESTION Is it true that goldfish which rise to the top of the tank are more likely to be overfed than dead?

OVERFEEDING can cause many problems for aquarium fish. It creates a build-up of rotting organic material that leads to cloudy water, algae growth and mould on gravel and plants.

Excess food begins a process of organic breakdown that swallows dissolved oxygen, leaving fish gasping for air. It can also cause nitrate build-up and low pH.

Swim bladder disease can be caused by overfeeding. Goldfish — especially fancy varieties — and betta fish are commonly affected.

They have round, short bodies which can compress their internal organs. When full, their digestive organs press against the swim bladder, making it difficult for the fish to function properly.

Swim bladders normally inflate and help fish stay properly afloat. When compromised, fish will float to the surface.

So when you see your pet bellyup, don’t assume it’s dead. If it’s still breathing, it probably has swim bladder disease.

This condition doesn’t necessarily result in fish floating to the top; other symptoms include a swollen belly, the fish sinking to the bottom of the tank, or swimming with its tail above its head (however, this is normal for some).

The cure is simple. Stop feeding the fish for three days and raise the water temperature slightly to increase metabolism. If this does not work, feed them cooked peas; the fibre will get things moving.

Joseph Gallier, Nottingham.

QUESTION The Mail stated there are 23 types of crocodile, of which six are dangerous to humans. What are the varieties, and where are they found?

FURTHER to the earlier answer, if you want to see all 23 crocodile species in one place, including the rare Indian gharial, visit the St Augustine Alligator Farm Zoological Park in Florida, U.S.

It opened in 1893 and has expanded to include other reptiles, monkeys and birds. The bird collection alone boasts rare species such as hornbills, cassowary, marabou, Cape griffon vultures, and Pesquet’s parrots.

John Pritchard, Ingatestone, Essex.