Under the surface: the fantastical world of aquarium hobbyists

An insight into the allure of fishkeeping as a subculture

By Sophie Caprioli

Amidst the coral polyp forest, an anemone creeps. So slow, its movement is almost imperceptible to the naked eye, the anemone moves by sliding along the surface using its pedal disc. It finally comes to a halt, finding pride of position resting atop the rock; its venom filled tentacles waving brazenly in the current.

This magical scene is not located beneath the ocean waves; this coral frag resides in the corner of my bedroom. The world of aquarium hobbyists is one of extreme dedication, whereby real fanatics will invest hundreds of pounds, committing their lives to the upkeep of nano reefs. Tanks as large as 536 litres are used to host a variety of different coral and fish species, such as mushroom corals (Actinodiscus genus) and blue tangs (Paracanthurus hepatus, better recognised as Dory from ‘Finding Nemo’).

The psychedelic colours of soft coral species are incredibly alluring; however, it takes careful planning and a lot of perseverance to care for such fragile creatures. Corals are highly susceptible to bleaching. Constant daily checks on salinity, pH, ammonia levels, and temperature need to be made and, even then, there may be some casualties.

Choosing fish friends to inhabit an aquarium is a strategic process. If predatory species, lurking in the tank, are desired, one must ensure that niches do not overlap. For example, the blue dot jaw fish and snowflake eel both inhabit the same cave territory, meaning keeping these two in the same tank would be akin to putting Tyson and Ali in the boxing ring. Some of my favourite predators include the lionfish (Pterois genus) and the boxfish (Ostracion cubicus).

The lionfish is a member of the scorpionfish family (Scorpaenidae). It lives up to its namesake by being well-equipped with venom-filled glandular tissues, located in their dorsal, pelvic and caudal fins. Despite its samurai warrior bravado, the lionfish has a gentle nature and, although painful, its venom is not capable of delivering a sting worse than a bee.

Despite its endearing appearance and inconspicuous name, the boxfish partakes in acts of chemical warfare. When injured or stressed, the boxfish secretes poisonous pahutoxin from specialised skin cells. Although the mechanism by which this toxin works is not entirely understood, it is thought that the pahutoxin is haemolytic in function, popping red blood cells in the gills of unsuspecting predators. In the small enclosed system of an aquarium, the toxin is lethal enough to eliminate all other fish in the tank. A nightmare of an aquarium keeper, right? Apparently not; boxfish are popular among aquarium keepers!

Last year, the IPCC (Intergovernmental Panel on Climate Change) released a report stating that if global temperatures increase by 1.5°C, coral reefs will likely decline by 70 to 90%. Currently, reefs throughout the world are in a state of decline, with sea surface temperatures having already increased by 1°C in the last century. With the natural world of coral reefs under threat, I call on coral lovers to extend their passion beyond the aquarium and into the ocean.

From Issue 18