• Species: Bengal Loach

  • Species: Botia almorhae

  • Species: Clown loach

  • Species: Rotkeil Severum

  • Species: Giant Gourami

  • Species: Hampala Barb

  • Species: Oscar

  • Species: Festivum Cichlid

  • Species: Filament Barb

  • Species: Spanner Barb

  • Species: Snakeskin gourami

Stocking Larger Community Tanks

26 May 2019


The basic rules for stocking communities of larger fish isn't really much different to stocking the standard communities of smaller fish, but there are some considerations that can make things more challenging. Obviously there's the issue that bigger fish demand more space (both physically and psychologically) so the aquarium has to provide sufficient space for these fish to feel at home and stay healthy. But there's also more subtle background factors like oxygen levels and pH changes that aquarists can largely ignore when smaller fish are being kept but can cause major problems in big fish communities.

Having stated the challenges, it's as well to be clear that big fish communities can offer some splendid opportunities. Big fish often have more presence than their smaller counterparts, and some of them can be surprising intelligent and interactive 'pets' more like dogs or cats than tropical fish. Many big fish are brilliantly coloured or exhibit bizarre body shapes that make them especially attractive animals to keep.

Barbs

The Spanner Barb or T-Barb (Puntius lateristriga) is an old favourite, one of the barbs kept by aquarists for generations because of its hardy nature and peaceful personality. Though fairly large, getting to around 15 cm in length, the Spanner Barb isn't nippy or aggressive, and this makes it a good companion for medium to large-sized non-aggressive fish such as Oscars and L-number catfish. Though it isn't brilliantly coloured, its black 'monkey wrench' markings are attractive, and unlike most other barbs, is robust enough to do well if kept singly. Small groups are often prone to bickering, so if more than one is kept, keep six or more.

The Hampala Barb (Hampala macrolepidota) is one of the newer barb species in the trade. It's an extremely handsome fish, streamlined and silvery with black markings on the body and orangey-red fins. Although one of the predatory barbs with a taste for meaty foods like crustaceans and insects, it isn't particularly aggressive and works well alongside tankmates of similar size. However, as wonderful as this gregarious and adaptable barb may be, it is very large by aquarium standards, easily reaching lengths of more than 60 cm within a couple of years (wild specimens get even bigger). As such, it's a fish for public aquaria rather than home aquaria, despite its regular availability.

Considerably more manageable is the Filament Barb, Dawkinsia filamentosa, (in older books, Puntius filamentosus). This is another barb that was once rarely seen but now frequently appears in aquarium shops. It gets to about 10 cm or so in length, and as its name suggests, develops long extensions to its dorsal fin. Colouration is somewhat variable, basically pearly-white with a pinkish iridescence, but some specimens develop distinctly rose or green-coloured hues. Filament Barbs are flighty, even nervous, so need to be kept in a fair-sized group of at least a half-dozen specimens and away from aggressive tankmates. But otherwise they're very adaptable fish; in the wild, they're even reported to inhabit slightly brackish water, so water chemistry likely isn't a major issue. Given their size though, it would be unwise to keep them in an aquarium smaller than 250 litres.

The Red-Line Torpedo Barb (Puntius denisonii) is one of the most popular barbs in the trade, but sadly, is often kept improperly, so has a reputation for not doing particularly well in the long term. That's a shame because it isn't a delicate species by any means; really, it's only unusual demand is that it shouldn't be kept too warm. Red-Line Torpedo Barbs are subtropical fish, and in homes with central heating can do perfectly well in unheated tanks. Otherwise, a temperature around 18-22 degrees C is ideal. They may be kept a little warmer, up to 25 degrees C, but only in lightly-stocked tanks with excellent water quality and plenty of oxygen. High turnover rates are essential, so big, powerful filters are a must. Otherwise this barb isn't too demanding. Maximum length is around 10 cm, water chemistry values aren't crucial provided extremes are avoided.

Loaches

Many of the larger loaches make excellent additions to big fish communities. The Clown Loach (Chromobotia macracanthus) is the classic example. In many ways a fine aquarium fish, the Clown Loach is adaptable and long-lived if kept properly. But many aquarists make the mistake of underestimating its eventual size, and this causes problems in the long term. Clown Loaches should reach at least 20 cm in length, and many specimens get to around 25-30 cm. Couple this with the fact they're gregarious so at least three specimens should be kept, and preferably five or more. Newly imported specimens can be a trifle delicate, so a period of quarantining is highly recommended, partly to get them fattened up a bit, but also to provide scope for medication if needed; deworming for example seems to be quite a common requirement. Clown Loaches are inept predators and generally ignore dissimilar fish. As such, they make fine companions for things like South American cichlids and large barbs. Given their size, Clown Loaches shouldn't be kept in tanks smaller than 450 litres.

The Pakistani or Yoyo Loach (Botia almorhae) is another good community tank loach. It gets to around 15 cm or so in length, so a group of them won't really be viable in anything less than 250 litres, but other that this requirement these are very undemanding loaches. They are peaceful and adaptable, and though it dislikes bright light, in a shady aquarium it will be very outgoing and active, even by day. Colouration is variable, basically brown marbling against a gold or silver background. Indeed, it is likely that more than one species or subspecies gets sold under the Yoyo Loach name.

The Bengal Loach (Botia dario) is very similar to the Yoyo Loach in terms of size and care. It's just as peaceful and also does well in groups of three or more specimens. Whereas the Yoyo Loach has mottled or marbled markings, the Bengal Loach has oblique vertical bands.

Gouramis

Pearl Gouramis (to 15 cm) and Snakeskin Gouramis (to 20 cm) are medium-sized Asian gouramis that work well in communities of medium-sized fish. They do well in groups and while they aren't overly active, they are far from shy, making them good specimen fish. They do best in tanks with lots of plants, but are otherwise undemanding, tolerating a broad range of water chemistry values and eating all sorts of small floating foods.

However, the classic big gourami is the appropriately-named Giant Gourami (Osphronemus goramy) that reaches 50-60 cm in length. This massive fish is rather ugly as an adult, but oozes personality, and quickly endears itself to its keepers. This is one of those few fish that become genuinely tame, and though it can become cranky and intolerant if kept in a small aquarium, given space this fish is very peaceful and gets along great with tankmates too large to swallow whole. Several colour forms are available, including a stunning silver variety, but anyone contemplating keeping this species should plan ahead carefully. Adults need an aquarium at least 750 litres in capacity, as well as massive amounts of filtration -- these greedy and omnivorous fish being notoriously messy!

Cichlids

The range of cichlids that are viable in big fish communities is far too large to cover here, but a few popular species may be mentioned here. Oscars (Astronotus ocellatus) and Severums (Heros spp.) are favourites, being quite placid animals outside of breeding. Oscars have now been bred into any number of colour forms, and though they are territorial fish, singletons can be peaceful, and even mated pairs are tolerant outside of breeding. Oscars are of course predators, but they get along fine with fish more than about two-thirds their size. Oscars don't eat plants, but they will uproot them, so are best kept in tanks decorated with bogwood and rocks.

Severums are somewhat smaller than Oscars, and herbivores rather than predators. They will eat soft aquarium plants, but leave robust things like Java ferns and Anubias alone. Several species are now recognised, including the stunning Rotkeil or Red-Headed Severum. Severums are peaceful except when breeding. Both Oscars and Severums are South American fish that prefer soft, slightly acidic water, but they are adaptable fish provided water quality is good.

Festivum Cichlids (Mesonauta spp.) are also from South America and share the same preferences. They don't damage plants though, and in fact appreciate the shade than live plants provide. Festivums are very peaceful, even sensitive fish that dislike boisterous tankmates, so choose companion species carefully. Their colours are highly variable and dependent on mood, but the oblique band running from the snout to the tip of the dorsal fin is distinctive.