I - Aquarium Dictionary

Updated August 12, 2019
Author: Mike - FishLore Admin
Social Media: FishLore on Social Media

Aquarium Fish Definition and Glossary

Ich :
also known as ick or white spot disease, Ich is a very common fish disease. The freshwater fish disease version is Ichthyophthirius multifiliis and the saltwater fish disease version is called Cryptocaryon. It appears as small white dots all over the fish's skin. It's actually a parasite that is just below the skin. Ich has a life cycle that consists of a free-living stage and a parasite stage when it attaches to the fish. After it has been attached to the fish for a while, it will break free and settle into the substrate where it will become a cyst, reproduce and multiply many times over. When these cysts mature they can swim and start looking for a fish host. This is a common disease and should be taken seriously if you want to save your fish. It has the capacity to wipe out entire tanks if not treated. There are many products on the market to treat this parasite. Please use a quarantine tank for any new arrivals to prevent an ich outbreak. Also look into using the following for treatment:
Ich Cure
Super Ich Cure on Amazon

Ichthyologist :
Icthyology is the study of fishes. An Ichtyologist is the person that does the studying. An Ichtyologist could work for a large aquarium, a museum or a university identifying fish species and documenting fish behavior and habitats.

ID :
usually short for Iridescent Shark but also for the word "identification".

Impeller :
is a piece of equipment inside powerheads and power filters that helps move water through the device. Sometimes natural wear and tear may reduce performance in powerheads and power filters and replacing the impeller can prove useful.
Impellers on Amazon

Inch Per Gallon :
refers to a rather silly guideline you'll come across that some hobbyists use to stock their aquarium. This "guideline" recommends stocking 1 inch of fish per 1 gallon of water. This is an extremely short sighted rule and only works on very small or juvenile fish. Larger fish species require much larger living quarters. A 1 inch pacu will not last long in a 1 gallon aquarium. Various factors come into play when stocking an aquarium such as fish temperament, how large the water surface is for gas exchange, the type of filter system used, water change regimens, etc. Please don't follow or believe this rule!

Infusoria :
are tiny organisms (protozoa) and algae that are cultured (grown) and fed to fish fry.

Internal Aquarium Filter :
any filter that needs to be operated inside the tank. Examples of internal aquarium filters are the undergravel filter, sponge filter and corner filter.

Invertebrate :
animals that do not have a backbone. In aquariums, invertebrates are snails, shrimps, crabs, corals, anemones, etc.

Iodine :
a saltwater aquarium supplement, iodine is used up quickly by the tank inhabitants (corals and invertebrates) and skimmed from the tank via the protein skimmer. It is crucial to use an iodine test kit before dosing iodine in your aquarium. In natural sea water, the iodine concentration is 0.03 - 0.06 mg/L (ppm). Lugol's Solution is a concentrated form of iodine used for dosing:
See: Iodine Supplement on Amazon