Siamese fighting fish, also known as bettas, got their name for their intense fatherly instinct. Male bettas build a nest of floating bubbles, coating each one with saliva so they won't pop, for the female's eggs. The male fights off everything—including the mother—to ensure the safety of the eggs. One might say he's more than a little overprotective. The incubation period is short, however, with the eggs hatching after 24 to 36 hours. The male continues to protect the newborns until they are ready to survive on their own.

White marlins are part of a group called "billfish," a term which refers to predatory fish in the family Istiophoridae. As their name implies, they all have bills that they use to attack prey. But that's not the only thing they have in common; white marlins are all very migratory and are often found in tropical or sub-tropical waters. Other members of the billfish squad include black marlin, blue marlin, sailfish, swordfish and spearfish.

The cobia is not that dangerous, but they are aggressive when provoked or attacked. They tend to thrash around with harsh tail movements after being caught during fishing. Cobia aquaculture facts state that it is difficult to catch a cobia, but it can be done with the correct type of bait. There are between seven and nine very sharp and stout dorsal spines, which can cause injuries. So, to prevent that, special care should be taken while handling these powerful fish.

Pink maomao are a type of sea perch with a flat body and forked tail; the only indentation on their body is the eye socket. Their amazing pink colour is why they are commonly nick-named "Pinkies". Females are pink to red whilst males are pinkish with yellow spots and a large dark blotch on their dorsal fin. Not a lot is known about the pink maomao species. They can grow to around 50 centimetres, but a more common size is around the 28 to 30cm range, with a weight of around 1kg. Larger pink maomao can weigh around 2kg. Young pink maomao are rarely seen, suggesting that this species reproduces slowly and only occasionally.

The Arctic Chars are cold-water fishes closely related to the Lake Trout and Salmon varieties. It has many characteristics similar to the Salmon and Trouts. The Arctic Char's English name has been derived from the Old Irish term 'cera,' which means 'blood-red,' referring to the red color on its body. Arctic Char enjoys the stature of being called the world's most variable vertebrate. These fish species have a large number of morphs all over their habitat range. With the color variations, ubiquitous morphs, and the differential size proportion it can reach.

Tilapia is considered to be one of the most unhealthy fishes that one can consume. The foremost reason being the circumstances of raising the fish, which is often in an enclosed area. Moreover, the fish also has a reputation of being a food item through which humans can get mercury poisoning. Even though tilapia originated in the Middle East and Africa, the fish is now farmed and available all over the world. Compared to it, the rainbow trout is considered to be one of the healthiest fishes for human consumption.

The speckled trout is known to communicate with one another via sounds in the water. During the process the mating, males are known to produce loud sounds which act as a courtship ritual to attract the females. Moreover, they also communicate by vibration, and visually. They search their prey visually and by vibrations in the water. They also get a good sense of their surroundings (irrespective of being shallow water or deeper channels) by the vibrations they feel around them.

Wonky Holes are underwater springs exiting from the sea floor. They were given the name wonky holes by the northern trawlermen who used to lose their gear and sometimes capsize their boats. Wonky Holes spew out a lot of rubble etc., and deposit it all around the hole. This in turn attracts soft corals and sea ferns to grow on the surrounding seabed and then comes the baitfish, squid, octopus and then of course predators like red emperor and large mouth nannygai.

Tripletails are called this because they appear to have three tails, a consequence of enlarged lobes on the posterior fins. A peculiar adaptation, which may be a means of protective camouflage, is the propensity of young tripletails to turn sideways in the water and float listlessly, mimicking floating leaves. Tripletails are carnivorous and in the Atlantic are sometimes sought by sports fishermen.

Sea sponges lack the ability to move, so most of them stay still at the same place, forming reefs. A reef is often formed of several species of sea sponges, or it may even include coral or other formations. A sea sponge animal has to live their lives amongst all other marine animals that live in the same area. Some sea sponges are also known for getting involved in the process of photosynthesizing endosymbionts, where they produce three times more oxygen than they take in. Hence, the oxygen that they produce benefits the organisms living beside them. Some shrimps also live in loggerhead sponges giving them protection against other predators.