Ted’s Fishroom

Betta macrostoma (Regan, 1910)

B. macrostoma is a large, colorful and expensive mouthbrooding species from Brunei (on the island of Borneo).  Like all of the mouthbrooding betta species that I know of, the males are the brooders.  Using the unofficial classification system I like for bettas, B. macrostoma qualifies as a large - big mouth - mouthbrooding species.  Adults can grow to the 10 - 12 cm length range.  Add to that their robust stature and you get a very impressive betta.  Behaviorially they are not as mean as B. splendens or the other fighting bettas, but they are pugnacious enough to pay careful attention to, just in case a conflict occurs.  Like all bettas they are very aware of their environment and have personalities. 

 I currently own four B. macrostoma.  They are F1 fish for which I traded some blue-eye rainbows, Pseudomugil cyanodorsalis.  I am very aware that I made the deal of the century.  In my defense, however, the transaction was initiated by the betta breeder who was looking specifically for that rainbow.  When I got them they were only 2 cm long and still in juvenile coloration.  Now, six months later, they are 5 cm and colored adolescents.  I ended up with one male and three females.

IF YOU HAVE AN EXTRA MALE AND NEED A FEMALE, I WILL TRADE!!!!

These are not the first B. macrostoma I have kept.  I embarrassed to admit that I killed a beautiful wild pair (male pictured above) with velvet.  That pair came into my posession from a friend who was hoping that I would get fry from them, but I was not successful.  The pair would spawn regularly, but the eggs were never fertile.  I even stripped the male of eggs on three attempts and tried to incubate them artificially, but they never developed.  I suspect that either of the parents were infertile.  I was hoping to get another pair and cross to the pair I had to test that theory, but they died before I had the chance.

I have gotten conflicting advice about spawning this species.  Some breeders say that so long as the water is soft, slightly acidic and cool (no higher than 76F) that nothing else matters.  Other breeders have told me that only young fish of less than 2 years of age are breedable, while others insist that only older fish of more the three years of age will be successful.  Since my first pair was wild caught, I do not know how old they were.  My current group were hatched in the early Spring of 2007, so they are just approaching a year in age.  The male started to color up about a month ago, and the females are definitely swollen with eggs.  I have not caught a spawn yet, though that does not mean they are not trying. 

I raised all four fish together in a 20H with driftwood and floating plants.  There were three ZooMed floating logs for territories as well, each claimed by its own betta.  I put in some blue tetras as dither fish.  The bettas are not picky eaters, and I fed them a variety of foods including flake, pellet and live worms (grindal, white and black).  They also like small crickets, which they attack ferociously.  During this growing time I kept the water moderately soft and slightly acidic (50 ppm TDS, KH 2 - 3 & pH 6.5 - 6.8).  Velvet is a softwater protozoan parasite, so keeping the water a little harder is a good preventative.  Unfortunately the parasite also likes cool water, which the bettas prefer, so I could not keep the temperature up at 80F to further thwart a velvet outbreak.

When the male started to color up, he and the largest female started to bully the smaller females and each other.  I decided to move the young pair to a longer aquarium, an approximately 23 gallon tank that measures 36″ x 12″ x 12″.  I decorated this tank with driftwood, two floating logs and lots of floating plants.  For dithers I added a school of Sawbwa resplendens, the rummynose rasbora, but one of them was brutally munched by a betta.  I will have to find something hardier…. or at least faster.  I am doing water changes with RO and lowering the pH with a tea made from boiling catappa leaf, and leaving a few of the boiled leaves in the tank.

 A note on catappa leaf.  Great stuff… but the tannin load is impressive.  I prefer to boil a bunch of leaves to remove most of the tannin.  I can then add a bit of the tea to get the benefits without totally discoloring the water.  Pre-boiled leaves decompose quickly, but do not add a lot more tannin to the water.

 The B. macrostoma pair has settled in nicely.  They have the space to avoid each other, but come into contact occasionally.  When this happens the male lights up and displays aggressively.  They are not fighting, which is a good sign, and I am hoping to see a spawn soon.