FishWiki

The fish of the week is the axolotl (Ambystoma Mexicanum).

Axolotls once inhabited the freshwater canals of Mexico, particularly lakes Xochimilco and Chalco. Now, they're extinct in the wild, with the last alleged sighting being in 2019.

These mole salamanders never grow up; they're neotenic so they remain in their larval, aquatic state throughout their lives. The exception to this is an interesting gene that forces metamorphosis.

They can be found in a variety of morphs (colors), including Leucistic, Melanoid, Copper, and Green Fluorescent Protein! Axolotls grow up to 12" long, and in captivity require 30+ gallons of water per axolotl.

Axolotls have gill stalks covered in soft filaments, legs with 4 or 5 toes, and a long, muscular tail. They also boast a fascinating ability to regenerate body parts, even entire limbs!

This non-annual killifish is native to Cuba where it is found mostly on the western side of the island in densely planted fresh and sometimes brackish waters. They prefer to swim near the muddy bottoms of slow moving or stagnant pools.

Males are usually 3.6 cm (1.4 in) in length while females are slightly smaller. The males are more colorful and become especially bright during breeding. Females can lay up to 10 eggs a day by depositing them individually on plant leaves. Most of their diet consists of insect larvae and microfauna. They do well in aquariums but are not commonly found in the hobby.

This species of tiny crab (only growing to be an inch wide) is native to the Hawaiian islands. It's commonly called the pom-pom crab or boxer crab because of its habit of carrying a sea anemone around in each of its claws, these resembling pom-poms or boxing gloves. Its Hawaiian name is kūmimi pua, meaning "inedible flower crab". They live in shallow reefs on sand/gravel where they can easily camouflage.

These crabs have a mutualistic symbiotic relationship with the anemones they hold in each claw. The anemones are fed and the crab uses them for defense, courtship, and for catching food particles. If an anemone dies the crab will propagate the other by ripping it in half. Multiple species of anemones have been recorded as being used by the crabs but they can also carry other organisms like sponges and nudibranchs while they look for replacement anemones. In the aquarium they can be kept with peaceful fish and other non-aggressive invertebrates.