Tips for selecting healthy fish:
• Clear Eyes (not cloudy)
• Undamaged fins
• Scales should be intact, parallel with body (not sticking outwards) and no red blotches
• No holes, ulcerations, or lumps
• Active, lively, normal swimming patterns
• No white spots (salt grain size) or white cottony growths on the fins or body
• Respiration rate should be regular and steady (in unstressed circumstances)
• Gills should be red inside, not faded or discolored, and not distended or puffy.
• Actively feeding
• Avoid selecting fish from a system that contains any sick specimens
Choosing fish that are healthy from the beginning will help avoid problems.
Goldfish can be kept in smaller ponds than Koi. They have been cultured for centuries and a variety of different species are available. Among the characteristics that determine the different varieties are tail length, color and the absence of a dorsal fin. Goldfish can grow to 30cm (12 inches) in length. Common varieties include: Sarasa, Comets, Red Fantails and Shubunkins.
Koi (carp) are the most well recognized pond fish. They come in a variety of different color patterns. Some koi have been reported to live up to 75 years and reach over 0.9 meters (3 feet) in length.
A basic rule of thumb is that goldfish require 11liter (3 gallons) of water per 2.5 cm (1 inch) of fish; koi need a minimum of 19 liters (5 gallons) per 2.5cm (1 inch)of fish.