The Goliath Tigerfish, Hydrocynus goliath, is a ferocious predatory fish native to the Congo River Basin in Africa. It can grow up to 1.5 meters long and has be known to prey on small crocodiles and tearing large catfish into pieces! It occasionally attacks human since it is able to sense low frequency vibration in the water. It prefers to hunt in fast flowing water where smaller fish struggle to swim. Its massive teeth perfectly slide into distinct patches along its jaw. The Goliath Tigerfish is very rarely kept in any sort of aquarium although I did manage to spot a few at the Singapore River Safari the other day! See video below 🙂
The Pictus Catfish, Pimelodus Pictus, is a small species of catfish with extreme long barbels. The barbels can even reach to the caudal fin! Pictus Catfish are active bottom feeders that are usually most active at night. They inhabit the Amazon and Orinoco river basins and are common in the aquarium trade. In captivity they are omnivorous and eat vegetables, blood worms and insects among others. They are relatively peaceful fish and can be kept with other fish of similar size. Larger Pictus Catfish, however, will have a go at smaller fish (small tetra’s for example). Pictus Catfish are non-territorial so a shoal of 5 or more will make this species of catfish feel more at home. Furthermore, it is important to provide plenty of plants, rock, caves and driftwood in soft water. A dimly lit aquarium encourages the fish to be more active.
The Pearl Gourami, Trichopodus leerii, is a beautiful community fish that is easy to take care of. They originate from lowland swamps of Thailand, Malaysia and Indonesia. Mature males display an impressive bright orange/red near their throat area. Also their anal fins are slightly more elongated than the females. Males can sometimes be aggressive towards each other and chase females when they want to breed, so ensure that there are sufficient hiding places with lots of plant cover. As with all gourami’s, Pearl Gourami’s have a labyrinth organ that breath air, so leave the surface of the tank exposed to fresh air. The mating display of the Pearl Gourami is unusual and very beautiful. Males constructs a large bubble nest among floating plants to impress the female. If the female is impressed, both begin touching each other with their modified ventral fins 🙂
The Uara Cichlid, uaru amphiacanthoides, is a large species of cichlid native to South America in Northern Brazil and parts of Guyana that can grown up to 30 centimeters in length. It inhabits clear water tributaries, particularly around submerged branches and tree roots. Uara Cichlids can be recognized by their large eyes and distinguishing large spot on the body. In the aquarium it is a surprisingly peaceful fish considering its size and the aggressive behavior of most other cichlid species. It can be housed together with tetras, angels and species of characins. Uara Cichlids do need be housed in large tanks of about two meters in length. These fish can be fed frozen foods such as blood worms or brine shrimp, but will also happily eat vegetables such as lettuce, peas and spinach. Dried foods will also be gladly accepted. Juveniles often feed on the slime coat of their parents, similar to what Discus do.
To grow vegetables in water from a fish pond full of nutrients might sound like a brilliant idea, but is it really profitable? A study by reaearchers from the Wageningen Univesity showed that more than half of the 1000 commercial aquaponic farms worldwide make a loss. This was mainly the result of low market value for the produced vegetables and fish that were farmed. Before starting an aquaponics farm it is important to look at the market prospects. A niche in the market needs to be found that could make aquaponics more profitable. Tilapia and catfish usually won’t make it because they sell for far to cheap. Perch, burbot and pike could be interesting alternatives for the European market as their market value is much higher.
Schematic overview of a aquaponic system. Illustration retrieved from Baliga Lab, Institute for Systems Biology
The Blackline Penguinfish, Thayeria boehlkei, also known as the hockey-stick tetra is a species of tetra native to the upper Amazon River basin in Peru and Araguaia River in Brazil. It has a distinguishing black line across its body which hooks downwards at its tail. It is highly recommended to cover the aquarium as these small fish have been seen jumping 2 meters out of the aquarium! Keep this fish in schools of at least 6 individuals (preferably more). The blackline penguinfish does not grow very large (max 7 centimeters long), so one does not need a very large aquarium to house a school of these fish. These fish are not too fussy concerning water parameters as long as the tank is cleaned periodically. This is a very peaceful fish excellent for a community tank. Goes well with other species of schooling tetra’s 🙂
NPR (2017). A Russian fish farming operation in Ura Bay in the Barents Sea
Consumption of seafood is expected to replace a considerable amount of meaty products in the future. Could widespread marine aquaculture in (open) coastal areas help in satisfying the global demand for seafood? Researchers from the University of California certainly think so. Using certain criteria they calculated that marine aquaculture could potentially produce 16.5 billions tons of fish per year or 4000 pounds per person! The question remains, however, where will the increased fish feed come from. Will high-protein vegetable crops be needed which production is based on land? Also, wild specimens need to caught in order to start a population of fish for breeding. Finally, care needs to taken on the implementation of marine aquaculture in coastal areas. Shrimp farms in South-East Asia have destroyed many coastal mangrove forests and discharged harmful contaminants in estuaries. Space is not necessarily an issue for marine aquaculture, it is more of applying it in a sustainable manner by rectifying the above challenges!
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The remote Anambas Archipelago in Indonesia has rarely been heard of, but that is part of its beauty as it still has pristine beaches with healthy corals! The archipelago consists of 240 islands and can be accessed either from Bintan or Batam by ferry which takes approximately 8 to 9 hours.
There are two main islands, Pulau Jemaja and Pulau Siantan. The ferry will most likely arrive at P. Jemaja first. P. Jemaja is a very laid back island with friendly locals. There is a long 7 kilometre beach called Pantai Padang Melang which has white sand and calm waters. Nearly all villages on the island can be accessed by road so renting a motorbike for a day is a good idea. In the capital of the island, Letung, a local boat can be hired called pompong to sail to nearby islands. I managed to strike a deal for Rp. 700.000 for one day (about 45 euro’s), which was considered cheap. With the boat captain and guide onboard, we went to three islands: P. Mangkai, P. Mubur and P. Impol. Along the way we saw numerous other islands as well. The snorkelling at P. Mubur was amazing with pristine corals and a lot of coral reef fish! P. Impol had beautiful green hills with palm trees and P. Mangkai had impressive rock formations.
Pulau Siantan is home to the capital of the Anambas region, Tarempa. This is a rather crowded place compared to Letung, but the people are just as friendly. There are more accommodation options and restaurants than in Letung. I stayed in the comfortable Sakura Hotel and Laluna Resto was my personal favourite for meals. The island of Siantan is rather mountainous so road access to other areas is rather limited. An impressive waterfall can be reached called Air Terjun Temburun. This waterfall has is a series of small lagoons where water flows slowly from one to the next. I went there during a dry period so the water level was not that high. Arung Ijau in the west of Siantan island is the best place to watch the sunset. Also in Tarempa pompong’s can be hired to go to nearby islands. Pompong’s are more expensive in Tarempa than in Letung and you will have to pay more than Rp. 1.000.000 for a days hire. On the day that I hired a pompong from Tarempa, we visited three islands: P. Nongket, P. Penjalin and P. Mangkian. P. Nongket was a very peaceful place with large boulders where one can swim through. Corals were very good here and it’s a good place for photography with calm clear waters, large boulders and underwater life. P. Penjalin is one of the remotest islands in the Anambas Archipelago and had spectacular rock formations. One of which had a rock that was one push away from falling down! The snorkelling was excellent to the south side of the white sanded beach. I spotted a school of Napoleon Wrasse! P. Mangkian also had good snorkelling, but the current was quite strong due to deep waters around it. Also here, I spotted a school of Napoleon Wrasse. Watch out for the black sea urchins as they can pierce your stomach if you don’t watch out! On the last day of my stay we chartered a small speedboat to the island of Rengek where there was good snorkelling at the south side of the beach close to the drop-off. P. Rengek is near Tarempa so chartering a boat to this island costs about Rp. 350.000. I shared this with friends so it became even cheaper than that.
All in all, a very worthwhile experience travelling to these lovely islands. I can highly recommend it! Friendly people, good corals and white beaches. Remember to always bring your plastic and other types of waste with you and don’t touch the corals in order to preserve this place!
Predatory fish are awesome in their own right, but are obviously not well-suited for a community tank setup. Here are several distinguishing features that predatory have. None of these features alone would identify a predator, but a combination of them is a worrying sign 😉
Size: Fish that are two or three times bigger than other tank mates might view others as food.
Torpedo body: Long arrow-shaped bodies are designed for sudden bursts of speed to catch prey. Pike and gars are good examples.
Teeth: This may sound obvious, but fish with long obvious teeth designed for grabbing and holding are bound to eat anything that fits in its mouth.
Whiskers: Species of catfish have long elongated whiskers for detecting prey in dark deep waters. Expect them to munch on any type of fish that gets detected with these whiskers.
Camouflage and hiding: Although some peaceful species use camouflage to avoid predation, some use it to hunt! Fish that burry themselves or blend in well with leaves prepare themselves for a surprising attack.
Eye position: Fish with forward facing eyes give them overlapping vision and in-depth perception for ambushing prey.
Pike (Esox lucius)
This could quite possibly be your worst nightmare!
Lamprey’s are a species of prehistoric jawless fish that latch onto other fish to suck blood. Lamprey’s have been around for over 300 million years. They are boneless fish without any scales. Despite the lack of jaws, they are able to suck blood by first using their circular rows of sharp teeth to grab onto the body of the fish. Lamprey’s then carve a hole into the fish with their “tongue” which is lined with sharp teeth as well :O! It then proceeds to suck the fishes blood. The victim fish usually does not die, but the open wound left at end can get infected which could indirectly lead to death. Some juvenile species of lamprey spend their first years of their life filter feeding in fine sediment of river mouths. After a few years, they start to undergo a bizarre metamorphosis of a few months where they develop their bodies for blood sucking. They then move to large lakes or oceans to feed on fish and even marine mammals.