Ornamental Fisheries and Aquarium Management
Ornamental Fisheries and Aquarium Management
This domain tests aquarium setup, water chemistry, ornamental fish breeding, and trade. The exam favours practical management over species lists.
Core rules
- The nitrogen cycle: ammonia → nitrite → nitrate by nitrifying bacteria. A new tank must be cycled before fish are added.
- Filtration includes mechanical, biological, and chemical. Biological filtration needs surface area and oxygen.
- Stocking rule of thumb: about 1 inch of adult fish per gallon (≈3.8 L) of water, adjusted for body mass and filtration. It is a guide, not a law.
- Livebearers (guppy, molly, platy) give birth to fry; egg layers include barbs, tetras, and goldfish. Breeders need conditioning, spawning media, and fry food.
- Quarantine new fish for 2–4 weeks; acclimatise temperature and water chemistry.
Worked example
A 60 L tank is about 15.8 US gallons. Using 1 inch per gallon, it can support about 15 inches of adult fish. If adult guppies are 2 inches, the guide suggests about 7 fish. If the filter is small or the tank is heavily stocked, reduce this number. The reasoning is based on waste output and oxygen demand, not on fish length alone.
Traps
Do not change 100% of the water at once; do not add fish to an uncycled tank; do not overfeed; and do not treat the inch-per-gallon rule as exact.