Catfish of the Month Right Arrow January 2004

Emerald Catfish, Brochis-Panzerwels (Germany), Common Brochis, Emerald Brochis, Green Catfish, Smaragdpansermalle (Denmark) - Corydoras(ln8sc1) splendens   (Castelnau, 1855)

Article © Heok Hee Ng, uploaded January 01, 2004.

Living jewels is a term encountered in more verbose writings on aquarium fish. Surprisingly though it is not used as often to describe the gaudy fish available to the tropical marine hobby. More often than not it describes freshwater fish. Now that I've mortally offended any marine aquarists swimming past, I should explain myself. The freshwater hobby appears more subtle; fish have to be very happy to show their best and, to my eyes, there is a larger range of colouration displayed from happy to unhappy fish. Even with not-so-subtle manmade creations like pigeon blood discus, coral blue gouramis, fancy angelfish and so forth, I think I can see this more in freshwater species than in marine. I may well be blissfully unaware of specific marine species that could shoot down my gross over-generalisation in colourful flames. Yet, as a sweeping statement, it holds some water I think?

Brochis splendensSo, why am I regurgitating the living jewel thing? I feel this month's species and its congeners (other species that are members of the same genus) are prime examples from catfish land; not least because of their more common name, Emerald Catfish. Often when encountered for sale they can look less than exciting with brown basic coloration and slate grey flanks. Take them home, look after them and (perhaps with some adjustment of lighting, water and surroundings) these fish will begin to dazzle. For me, this is more rewarding than buying an already dazzling fish. That is my point.

It is remarkable that Brochis fade in such a way and indeed that they polish up so readily. When I was collecting these species in the wild they were pulled from impenetrably muddy waters yet bore the most dazzling green flanks even as small (less than 1”) fish. You may ask how I collected a shoal of them in such murky conditions with only a hand net? Patience? Knowledge? Actually, luck and a bit of lateral thinking. While others were busy collecting anything that moved (and quite a few things that didn't) with a great seine net or generally thrashing around scaring everything off in a 20 meter radius with hand nets, I paused to rest in the tropical afternoon sun. Being on a fish collection trip I was naturally watching the uniformly brown water even in moments of pause; it was then I saw a little bubble. A few moments later: another bubble. This is common when collecting in soft-bottomed habitat as recent footprints release gases trapped in the rotting mass of leaves that makes up the river “bottom”. But this area had not been trampled on recently. I continued to observe these bubbles appear every minute or two.

It suddenly dawned on me that I was watching something I had witnessed a hundred times before, but just from a different point of view. These bubbles were air released by fish that had come up to the surface to gulp it. Not (I worked out later) the initial, headstrong ascent to reach the surface, but the release of gas on the way down. My head filled with the idea that a huge shoal of something was right in front of me, hidden by the gloomy water. Often when wading through murky water it doesn't do to consider what may be three inches in front of your right foot, but today I had a theory to test.

At the next bubble I waited a second and then pulled the hand net through the area of water under the spot. This pulled out the Brochis you see in the picture. All this was recorded on video (maybe one day I will be able to put it online – mainly it is fairly dull footage of me going, hey, look another bubble), but another bubble yielded another Brochis. I was rolling. This technique appeared to yield good results (although one person can rarely compete with the effectiveness of a seine net) and even turned up a Corydoras ambiacus – the only one collected that trip. These fish were found in about a foot to two feet of water among soft short reeds, flooded grass and tall reeds. About 10 meters of riverbank was sampled.

Brochis splendens
Brochis splendens
As described in the text, freshly collected Brochis
Juvenile Brochis showing mottled pattern, red fins and high dorsal

These were young fish; they just had a little look of the "Hi fin Corydoras" about them. "Hi fin Corydoras" is a name with which unscrupulous, ignorant or just plain hopeful aquatic tradesmen label young Brochis splendens. At around the 1 cm mark, they are easy to mistake for Corydoras and they have fabulous red fins, the most striking being the disproportionately large dorsal. Young fish are also mottled; with age this gives way to spots. At around 2cm (or an inch) in size the fish shed all but a nod in passing to this appearance and assume adult form (with a few remaining spots on the helmet and dorsal area - as shown in the bottommost picture - that recede, like a human male's hairline, with time). Here aquarists will notice the greater number of rays in the dorsal fin that sets this genus apart from Corydoras. Around this size these fish also don their emerald cloaks, that are worn - in good conditions - for the rest of their lives.

Some suggest that these fish are more brightly coloured the murkier the water in which they are living. This seems plausible, but somewhat pointless to recreate in a home aquarium. OK, your fish may look great but all I'm looking at is a tank of chocolate milk shake. Mind you, I know some catfish keepers daft enough to attempt this – we are, after all, a group of people dedicated to keeping fish we don't see too often. Happily these fish attain at least a close approximation of their wild glory in the home aquarium especially (I personally feel) if kept in direct sunlight. Several spawnings of this species have now been recorded and young captive bred fish appear to continue the emerald tradition of their forbears.

So, how valuable is your emerald? There are three species of Brochis. These range from least common, most expensive B. britskii, through B. multiradiatus to the most common, least expensive fish that is the subject of this article. How do you know what you've got? B. splendens has fewer rays in its dorsal fin than the other two. B. multiradiatus, also known as the hog nosed catfish has a real snouty phizog and B. britskii has an armour plate covering its white "throat" area. We have pictures of all species of Brochis in the cat-elog, where you should be able to see what I'm talking about.

I often think this species should really hold that place held by the Bronze Cory (C. aeneus) in your local fish shop. A more gregarious, cheap, hardy, peaceful and colourful naturally occurring species is hard to imagine.

Brochis splendens

Copyright information for the images used in this article can be found on the species' full Cat-eLog page.

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