The secrets of keeping and breeding the Chocolate gourami won't be easily unwrapped, says John Rundle.
Certain fish are not only difficult to breed but can be troublesome to keep. One is the Asian labyrinth with the apt name of Chocolate gourami — and the far from appetising scientific name of Sphaerichthys osphromenoides.
Where is this fish from?
S. osphromenoides can found in Indonesia, Sumatra and Borneo and Malaya in shallow waters in swampy areas that have heavy plant growth — or in very acidic water that has no plant growth because of low mineral content.
What water parameters does it like?
Published information confirms this fish survives predominantly in this mineral-poor water with a pH range of 4-6 and hardness values of 0.5-6 DH.
So it won’t be easy to keep in the aquarium?
Meeting such water parameters in the aquarium just with water direct from the tap will not be not easy. I’m lucky, as where I live the tapwater is very soft and has a pH varying between 6.5-7. With these conditions I have no problem acclimatising my fish.
How do I set up for them?
I started to set up a 76 x 30 x 30cm/30 x 12 x 12” tank to hold them the day after I first saw mine for sale. It had a gravel substrate and was heavily planted with Java fern (Microsorum pteropus), Vallisneria and clumps of Java moss (Taxiphyllum barbieri).
The heater/thermostat was set to 25ºC/77°F, a similar temperature to that in the dealer’s tank, intending to slowly raise it to 27ºC/81°F. My tapwater was not too dissimilar from the shop water.
Don’t subject these fish to sudden changes in temperature and water conditions.
My lighting was kept subdued, with just a 15w low energy light on a switch set for a light cycle of ten hours on and 14 hours off.
In the past I used various methods of filtration for Chocolate gouramis, from undergravel, internal power filters to internal standard sponge filters. This time I used the Hamburg filter which consists of a wall of 25mm/1” thick aquarium sponge fitting completely across one end of the tank with a 5cm.2” gap that forms a sump.
I fitted two uplifts from sponge filters, but without the round sponges, and these fittings drew water through the sponge wall and back into the tank.
The wall provided a large area for biological material to collect.
How do I sex them?
The dorsal fin is pointed in the male and rounded in the female. To check is not easy because for most of the time their dorsal fins are closed to the body. I have only been able to definitely sex them when they are courting and preparing to breed.
The males at this time show a pronounced cream to white edge on the dorsal fin and cream stripes on the chocolate body. Females are rounder and show less colour.
Does this fish have any special needs?
It likes to be kept warm between temperatures of 24-28ºC/75-82°F. When visiting Malaya I saw one Chocolate gourami in a rubber plantation irrigation ditch where water temperature was well above the top end of this range.
When I kept them at 24ºC/75°F they were pale and did not survive long.
They must have live foods too. You may get them to take dry foods, but they will not survive long on this diet. All the Chocolate gouramis I have kept would not touch dry foods.
What would be a balanced live diet?
My fish would enjoy Daphnia, bloodworm, Grindalworm and whiteworm. I managed to get some to take frozen bloodworm too.
I feed whiteworm only once a week to whatever my fish species. It can be high in fat but still excellent for bringing fish into breeding condition.
Why is the Chocolate gourami not seen that often?
This could well be because of those special requirements. However, I have seen them looking good when the dealer has taken the trouble to meet their needs.
Is it a particularly good community fish?
It’s not one for such a set-up; I have never kept the Chocolate gourami in a tank with other species as they prefer a quiet life and do not react well to disturbance and quick movers around them.
When disturbed they will move with quick jerky movements and go very pale. During this period of fright they will remain motionless until feeling safe.
How about sexing them? Is it difficult?
Get more than just two fish because they are not easy to sex. Often the only way is when a pair decides to show signs of willingness to spawn. I bought all eight fish on sale.
Is breeding them a very difficult process?
I have only managed to breed them this time round.
From my purchase of eight, two started to show positive signs of being a pair. The male developed some stronger colours and was seen displaying them beside a fish that I assumed was a female. He would then chase away the other inmates.
I set up a 40 x 30 x 20cm/16 x 2 x 8” tank without gravel substrate. Java fern and Java moss were liberally placed for heavy cover and the filter was a standard sponge type. Temperature was set to 27ºC/81°F and the only lighting was daylight from the fish room window.
After a couple of days the selected fish had settled and were feeding in clear areas of the tank. Then one day I observed what looked like a very small bubble nest among Java fern leaves that were laying on the surface.
I did not see the egg-laying process or the female retrieving the eggs to hold in her mouth, and the only indication of breeding having taken place was when the male came out of the plants to feed while the female remained hidden.
According to other fishkeepers, spawning should take place near the bottom of the tank where they partially embrace. The female then expels yellowish eggs which she stores in her mouth.
Numbers of eggs can reach about 40 to 50 and incubation times vary according to where you search for information.
When I was able to see the female I could see that her throat looked swollen — a good sign she was holding the eggs — and at times she ventured to the surface for air. I removed the male in case he decided to annoy her and cause her to discharge or swallow the eggs before they had hatched.
Ten days from when I first saw that male’s swollen throat in among the surface plants was a very dark-coloured fry about 5mm in length. After 45 years of breeding aquatic animals I had finally managed to breed and cross off my list another of those 'problem' fish.
Rearing for the next generation
I read that the fry must be fed soon after free swimming or will soon starve, so I placed live brineshrimp nauplii in the tank. As the young were all at the tank’s surface I placed a light source on the cover glass to attract the light-sensitive brineshrimp.
The fry were feeding well and made a rough count of about 30. Each day I removed any uneaten brineshrimp as they can be a major cause of pollution and death of larvae or fry when breeding fish. This also allowed for a small water change each day. As the fry grew I added Grindalworm and selected small live bloodworm to their diet.
I did lose some fry and young fish along the way, but was able to raise 20 to young adults which were passed on to members of my local fish society and a local dealer.
Did you know?
There are four species in the genus: Sphaerichthys osphromenoides, Canestrini, 1860; Sphaerichthys vaillanti, Pellegrin, 1930; Sphaerichthys selatanensis, Vierke, 1979 and Sphaerichthys acrostoma, Vierke, 1979.
When J. Reichelt took S. osphromenoides to Germany in 1900 he thought it was a livebearer. It was next considered to be bubble-nesting egg-layer. In the late 1970s it was found to be a mouthbrooder!
This item was first published in the December 2009 issue of Practical Fishkeeping magazine. It may not be reproduced without written permission.