Breeding Dicrossus maculatus
by Sal Silvestri
from Wet Pet Gazette, Norwalk Aquarium Society
Volume 53 / Issue 1, July-Sept. 2004
Aquarticles
Background
I have kept and bred Dicrossus filamentosus, but I never saw (except in pictures)
Dicrossus maculatus until 3 years ago. You can imagine my excitement when I saw
it available in a wholesaler's list. I immediately ordered 12 fish. After almost 30 years
a legend became a reality.
Introduction
This species was found at Lago Maximo and Jose Assu as well as branches of the Amazon
River near Tonantins, the Rio Javari and Rio Tajapuru. Little is known about the
distribution range of this species. Reliable records stem from the vicinity of the city of
Santarem.
Description
D. maculatus resembles the widely known D. filamentosus and only larger
males exhibit distinct features which distinguish them apart. While the male D.
filamentosus develop a clearly lyretail (forked) caudal fin, the males of D.
maculatus grow an oval to slightly lanced (spaded) tail-fin, bluish with a dense
pattern of vertical bands. The female's is round and transparent, without any design. In
addition, D. maculatus also have much longer ventral fins. The males of the
latter species are larger and may reach up to 4 inches TL. In contrast, the females may
only reach 2 ½ inch TL.
Care
When my 12 fish arrived, they were set up in a 20 gal high tank. The fish were juveniles
and at that size they weren't sexable. They were housed with 6 juvenile Apistogramma
maciliensis and one small albino Ancistrus bushy nose pleco. The tank had
two Anubias sp- nana plants, whose leaves would hopefully be used as the spawning
media and a very LARGE clump of Java fern, which covered half of the tank! Since they love
to masticate the substrate in search for food, a fine medium as substrate (sand) and
especially small foods - i.e., Artemia nauplii (baby brine shrimp) are
recommended. The water was regular tap water. The pH fluctuated between 6.8 and 7.2, with
a GH of 6 degrees. Temperature was set at a steady 80 degrees, and water changes of 25-30%
were done weekly. This is very important since they are very sensitive to water condition.
Food: as with any other fish that I am attempting to breed, I provided them with a
varied diet high in protein. They were fed twice daily with a rotating menu of live baby
and adult brine shrimp (I never use frozen brine), frozen bloodworms, live blackworms
(which I use sparingly .. 2-3 times a week), frozen daphnia, and a good paste food (my
home made recipe). Note: since D. maculatus has a small mouth, the bloodworms and
blackworms were chopped to small pieces to make it easier for them to eat it. Given this
and the frequent water changes, it wasn't long before they started showing sexual
dimorphism. I ended up with 4 males and 6 females (2 died). At this point the Apistos were
also showing sexual dimorphism, but this is another story!
Breeding behavior
At this point I contemplated whether to move the entire colony to their own tank or just
remove 2 pairs and see what would happen. Since all the fish were doing well, I removed
all but 2 males and 3 females of D. maculatus and 2 pairs of the A.
maciliensis. Reading that these fish demand soft and acid water, I mixed 50% RO
(Reverse Osmosis) water with my tap water. This gave me a 6.5 pH and a GH of 2.
As time passed, the males got larger and they started to show some red coloration on
their dorsal and caudal fins. To be honest, at first, all the fish hid in the large mass
of Java moss, only to come out to eat. But, I soon saw one female hanging around one of
the anubias plants. She started to pluck on one of the leaves and chased any fish that
came within the immediate vicinity. It wasn't long before I saw her coloration change. She
lost her two rows of black spots and was replaced by a large black lateral band. About
three days after I noticed this change of behavior, I noticed that she was hovering around
one particular leaf, and she had developed light yellow pectoral fins and a red anal fin.
She was protecting the area more intensely. Upon closer observation, I noticed a patch of
light beige colored eggs on the leaf she had cleaned. At this point even the male is
chased away and the female cares for the eggs alone. Once spawning is finalized there's no
trace of bonding anymore. At this stage the female positions herself on top of the eggs
and fans fresh water over the eggs without interruption.
The eggs hatched after three days and immediately the larvae were relocated by the
female to a pit/depression in the sand. The site is changed at least once a day. She
preferred depressions near roots of plants. My anubias plant still had the plastic pot on
it and she loved to deposit the brood inside the pot. I guess because they were perfectly
camouflaged against the beige gravel. After 6-7 days the fry are free swimming, and the
"proud mother" began to herd the brood around the tank. The mother would always
stand on top of the feeding school. Any fry that stray away from the school is caught with
the mouth and re-deposited in the school. At this point she became a "Terror"!
Everyone hid. She attacked any moving objects (including my finger!). Everyone knew that
she ruled the tank!
Raising the Fry
As they became free swimming I started feeding baby brine shrimp, which I sprayed with a
turkey baster, over the clump of Java moss. This was done because most of the time the
brood were foraging inside the Java moss. I estimated that there were approximately 50
fry. At this stage the water changes were done very "carefully". The water was
siphoned into a bucket, which was carefully checked for any fry that were siphoned out!
Since this was the first spawn, I didn't want the fry to be picked-off by the other
residents in the tank! So, in order to guarantee that I would have some surviving fry, I
decided to remove half of the clutch. I placed them in a 15 gal tank, which was filled
with 70% of the water from the tank where they hatched and 30% straight tap water. The
tank was bare except for some Java moss. My filtration was a sponge filter and a corner
box filter. A 30-40% water change was done weekly. I also put a juvenile bushy nose
catfish (Ancistrus), with the fry, to eat any uneaten food. Even with this
regiment, the fry grew slow. A special observation that I made was that there were not any
noticeable differences in size between the fry left with the parents and those raised
separately. My past experience has always been that fry left with the parents always grew
faster! At about 4 months old, they were approximately ¾". At this age and size, I
included finely chopped blackworms and bloodworms in their diet. At about 5 months old,
they were a good 1" and the sexual dimorphism started to be noticeable.
In this spawn, I ended up with about 10% males. This was mainly due to the low pH,
which seemingly favors the development of female offspring. The subsequent spawn was done
with straight tap water… in this spawn almost 40% were males.
Conclusion
Despite what I read about this fish, I found them to be quite hardy, and easy to work
with. I enjoyed working with them immensely and the males are very impressive when fully
grown. If you are looking for a bit of a different dwarf, give the maculatus a
try. You will not be disappointed.
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