Giant Puffer Fish

Tetraodon Mbu.
A carnivorous freshwater puffer fish that originate from the middle and lower sections of the Congo river in Africa, as well as parts of Lake Tanganyika. It is not sensible, however, to keep these fish with other puffer fish or semi-aggressive fish.
The "puffing" behavior usually occurs when the fish is in danger or stressed, it is therefore not advisable to encourage the fish to 'puff up' on purpose.
It is also dangerous for the fish to 'puff up' with air and so it should only be caught in a volume of water rather than netted. When handling the fish (also not recommended unless absolutely necessary), latex gloves should be worn by the handler since the spines on the fishes skin contain the neurotoxin Tetraodotoxin.
Unlike many other freshwater puffer fish, the Tetraodon Mbu does not benefit from being kept in brackish conditions. It should be kept in a large tank with a clean supply of freshwater with a pH range between 7.0 and 8.0 and a temperature of 24 to 26 degrees C. The water hardness in the tank should be 10 to 12dH.
They are very sensitive to levels of ammonia nitrite and nitrates, so depending on the eating habits and size of aquarium it is highly recommended to regularly conduct 30% water changes every 7 days. One should also remove uneaten pieces of food left in the aquarium.
Remember, whilst the juvenile Mbu may look cute in the aquarium store, they usually grow to 75cm.
It is important to feed a mixture of food to the Mbu not only to ensure they receive plenty of vitamins and minerals, but also eat food sources that contain bones so as to maintain the puffer's beak (teeth). In the wild, Mbu regularly feed on freshwater shellfish such as mussels, and so the beak continues to grow throughout its life to compensate for the abrasive effect of eating shellfish. Thus, if the puffer is fed on a diet of only soft foods, the beak will eventually give the puffer an overbite and prevent it from eating any food.

Photo by Dusko Bojic

Red-bellied Piranha

Pygocentrus nattereri
This fresh-water carnivore have the reputation of being one of the most ferocious freshwater fish in the world. Their short jaws certainly are very powerful and lined with razor sharp teeth, well able to take a chunk of flesh out of much larger fish. As their name suggests they have a reddish tinge to the belly. They grow to a maximum of 33 cm and a weight of 3.5 kg.
These fish form big shoals. They predominantly eat other fish but myth suggests they will attack any creature, whatever the size, if it is injured or struggling in the water.
These fish have a very good sense of hearing, using a special line of sensors down the sides of the their bodies, called the lateral line system. This enables them to find struggling prey in murky water.
Piranha originate from Argentina, Bolivia, Brazil, Colombia, Ecuador, Guyana, Paraguay, Peru, Uruguay and Venezuela.
Photos by Dusko Bojic.

Tiger catfish

Pseudoplatystoma fasciatum
As the name suggests, these catfish have bold stripey and blotchy markings along their sides, in shades of bronze and brown. Like other catfish they have a series of sensitive whiskers or barbels that surround the mouth and allow catfish to search out their prey after dark, or in very cloudy water. The eyes are small, also indicating that this is a species that relies less on sight and more on other senses. These fish can grow to 130 cm.
Tiger catfish live in river channels and areas of flooded forest in the Amazon and Orinoco river basins, where they patrol the bottom looking for food. They are most active after dark, spending their days well hidden under stones or logs.
Tiger catfish spawn in January. The eggs are fertilised as they are shed into the water. A single female can produce millions of eggs: over 150,000 eggs per kilo of her body weight. Juvenile fish spend more time in flooded forests where, in amongst the branches and roots, they are safer from predators.
This fresh-water carnivore originates from Bolivia, Brazil, Colombia, Ecuador, French Guiana, Peru and Venezuela.
Photos by Dusko Bojic.

Giant Gourami

Osphronemus goramy
Gouramis live in shallow weed-choked pools, where oxygen is sometimes in short supply. Being able to breathe mouthfuls of air is very useful in these conditions. They feed on the weed itself and almost anything that lives amongst it like fish, frogs, etc.
The males are usually aggressive towards each other. They may engage in violent fights as seen in Siamese Fighting Fish, or highly ritualised aggression, with the so-called 'kiss' of a Kissing Gourami.
When Gourami's are ready to breed, they build a nest of plants at the surface of the water suspended with bubbles. The eggs are guided in, then after about two weeks the fry leave the nest.
Giant Gourami originate from Malaysia, Indonesia, Vietnam and Thailand. They reach the size of about 70cm.
Photos by Dusko Bojic.