Fish reproduction
Videos
Fish reproductive organs include testes and ovaries. In most species, gonads are paired organs of similar size, which can be partially or totally fused. There may also be a range of secondary organs t
A pair of bettas spawning under a bubble nest.
3. Ovary of a female Atlantic cod
Salmon eggs in different stages of development. In some only a few cells grow on top of the yolk, in the lower right the blood vessels surround the yolk and in the upper left the black eyes are visible.
Diagram of a fish egg: A. vitelline membrane B. chorion C. yolk D. oil globule E. perivitelline space F. embryo
Parasitism
Videos
Parasitism is a close relationship between species, where one organism, the parasite, lives on or inside another organism, the host, causing it some harm, and is adapted structurally to this way of li
Fish reproduction
…started capturing deep-sea anglerfish, they observed that all the specimens collected were female; furthermore, many of them had what appeared to be parasites attached to them. It turned out that these "parasites" were highly reduced male ceratioid anglerfish; the males of all species of anglerfish are much…
A fish parasite, the isopod Cymothoa exigua, replacing the tongue of a Lithognathus
Head (scolex) of tapeworm Taenia solium, an intestinal parasite, has hooks and suckers to attach to its host
The parasitic castrator Sacculina carcini (highlighted) attached to its crab host
Human head-lice are directly transmitted obligate ectoparasites