Celestial Eye have deeper bodies and shorter fins, and have selectively bred for these features as required by the British standard. In recent decades, the Chinese have crossed Celestials with several other breeds, most commonly Lionheads, Ranchus and Pompoms, producing much larger fish with short ranchu-like fins and very deep, blocky bodies, often with nasal 'bouquets' (pompoms) and rudimentary headgrowths. Some of these crosses tend to be less animated swimmers, especially those that possess a short, sharply downturned, ranchu-like caudal peduncle with flared and short caudal fins, traits which are otherwise uncharacteristic for the breed. Such fish can be quite sedentary, spending
Largetooth cookiecutter shark and sparsely scattered light-emitting photophores on the belly. Most specimens have lacked the dark "collar" found on the throat of "I. brasiliensis". However, a specimen caught in 2004 off the Azores did possess the collar. The maximum recorded length is . Based on its smaller dorsal and caudal fins, the largetooth cookiecutter shark is believed to be less active than "I. brasiliensis" and an overall weak swimmer. Much of its body cavity is occupied by an enormous oil-filled liver, which allows it to maintain neutral buoyancy in the water column with little effort. Unlike "I. brasiliensis", this shark possesses binocular