My 30-litre Freshwater Reef Tank The idea behind this tank is to create a freshwater aquarium where invertebrates rather than fish provide the focus on interest. In particular I wanted a variety of species with as many as possible coexisting and breeding. Hardware The tank is an Aquarium Systems ‘Mirabello 30’ system that a friend passed along to me after she upgraded to a larger tank. It had been used as a mini reef system, but being a freshwater aquarium guy it was quickly gutted and a freshwater substrate added. Specifically there is a bottom layer of pond soil covered with a deep bed of smooth silica sand mixed with a bit of gravel. Plants seem to thrive in this sort of substrate, as do burrowing invertebrates. Over the years the filter and the heater both died, so had to be replaced with new units. The light is a compact 11W fluorescent tube. Plants Because of the low wattage lighting, shade-tolerant plants were chosen, specifically Anubias, various Cryptocoryne hybrids, Java fern and Java moss. Oddly, the Java fern hasn’t done especially well, but the others have thrived. A few surplus Vallisneria plants have been added, and these seem to be surviving reasonably well. Plants play two critical roles in this system. Firstly, they provide cover for the invertebrates, particularly juveniles and moulting shrimps. Secondly they trap and collect food particles and algae, and this makes clumps of roots and Java moss useful feeding areas for the shrimps and snails. Fish Only a few fish are included in this system. At the moment there is a single bumblebee goby; four peacock gobies, Tateurndina ocellicauda; a school of Aspidoras pauciradiatus; and rogue male Nomorhamphus of some kind who won’t mix well with any other halfbeaks. Invertebrates The selection of freshwater invertebrates is limited compared to what is available to marine fishkeepers, but I’ve still been able to collect some nice species. Apart from pond snails and the inevitable Malayan livebearing snail Melanoides tuberculata used to keep the substrate clean, the following species have been added:
None of the snails damages the plants, and interestingly the snail-eating snails don’t seem to molest the larger snails, only the smaller species. Malayan livebearing snails are definitely consumed, as are Physa spp. The yellow helmet snails are new to me. They are large, with a shell length of about 4-5 cm, with grey bodies equipped with long tentacles. They appear to be omnivores and haven’t yet shown any sign of damaging plants. But they enjoy meaty foods, and in snail terms at least will speed towards frozen bloodworms and mysids, quickly engulfing them with their long proboscis. Breeding The shrimps breed freely, with each generation of shrimps reaching maturity within a couple of months. From a founder population of six specimens, there are several dozen adult shrimps in the tank now, even with surplus shrimps regularly being removed to other tanks. The nerites lay their eggs on solid objects, particularly gravel particles, regularly but as others have reported the larvae do not appear to develop in the aquarium. By contrast the snail-eating snail Clea helena does appear to be breeding in the tank. Eggs are laid singly in small transparent structures in crevices and on solid surfaces. It isn’t obvious to me how long they take to hatch, but presumably the juveniles crawl into the sand and develop there. Juvenile snails about 5 mm long may be spotted on surface occasionally during the daytime. Maintenance This tank has proved to be very easy to maintain. Feeding the snails is not really required, though they do enjoy algae wafers. Mostly they eat algae and decaying plant material. The snail-eating snails appear to be eating small snails and perhaps the occasional bloodworm or catfish pellet. Water changes are modest, 25-50% every couple of weeks. The addition of plant food to the tank doesn’t seem to upset the invertebrates. All in all, a very easy aquarium to keep! |
The tank is thickly planted with Anubias, Cryptocoryne species and Java moss
Sold as yellow-helmet snails, this unknown species may be Tylomelania, here feeding on mysis
Cherry shrimps have turned out to be great additions to the system, breeding readily
Snail-eating snails (Clea helena) seem to have done a good job eating the small snails that become pests while ignoring the large decorative species like nerites.
Nerite snails (Neritina spp.) do a good job of cleaning away algae from the glass
One of four Tateurndina ocellicauda, the males of which promptly claimed the caves and quickly begain guarding clutches of eggs
Juvenile Clea helena, shell length about 5 mm
A fun addition to the tank: an unknown species of Rineloricaria
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