Bullrouts are a member of the Scorpion Fish Family (Scorpaenidae) and are
feared by most people due to their venomous spines. A native of Eastern flowing steams
of NSW and Queensland in Australia, they inhabit both fresh and salt water. Luckily to
date I have not been spiked by them as, even though we handle them every week, I take
extreme care. We hear the horror stories that customers tell us of their experiences
with bullrouts, the pain and swelling are frightful so be warned - take care near
At Aquablue we grow bullrouts for the aquarium trade for those enthusiasts who want
something different in their tanks. They are a very tough, hardy species which are
perfect for tanks with other aggressive territorial species such as Barras, Cod, and
Oscars, etc. They are basically a nocturnal species which become quite active in the
tank at night, but during the day just basically pretend to be a rock, hardly moving
except if food comes its way then it will inhale it and back to motionlessness.
Bullrouts grow large to over 600grams but generally the ones we sell are in the 100
to 250 gram range. They can live happily in both marine and freshwater and anything
in-between. They live on a diet of shrimp, fish, worms and yabbies. Also some
indications they eat weed as they do regurgitate weed into our tanks after capture from
the ponds but it is not clear whether they have specifically eaten the aquatic weed or
if this has just been consumed as an added extra when eating the shrimp living in the
weed beds. In our tanks we feed them gambusia, shrimp and yabbies which we have plenty
of and are easy to catch.
There is not a lot known in the literature available on breeding bullrouts. We
capture roed up females and running males in April (autumn) and they do seem to school
up after heavy rain at that time in this region. Males always seem to be smaller than
females from our experience. For example I captured some breeding stock to do some
artificial breeding experiments in my hatchery a few years back. We finish breeding
Silver and Golden Perch in March and do not start breeding Bass, Mullet and Bream till
May so decided to do some Bullrouts for fun/terror in April.
We went down to the local hardware and purchased a set of leather riggers gloves and
a set of PVC heavy duty gauntlets and but on both pairs before handling them and it
worked AOK. We captured a total of 38 Bullrouts ready to breed on the 7th & 8th
April 2003. Of those 38 fish only 7 were males and weighed in from 95 to 175 grams.
The balance were all females from 210 gram to 550 gram. All were gravid with an
extremely swollen abdomen. We have never caught a Bullrout over 200 grams which is
male, that may mean nothing or perhaps they all start male and then turn female as they
get older. If anybody out there knows we would be interested to hear from you.
Knowing nothing about the breeding of Bullrouts we just decided to give it a go and
see what happens. We have heard reports that small bullrouts are seen in freshwater
impoundments where access to salt water is prohibited so we decided to breed them in
fresh and see what happened. We tried injecting them with HCG - a human gonadotrophin
- at the same rates we would try with Australian Bass. We did this as a starting point
as we regularly catch them in the wild in our bass nets. Females we injected at a rate
of 1000i.u./kg and males at 250i.u./kg. The freshwater was kept at 18°C as this is
the temperature we do the bass at and equivalent to river temperatures in the region at
this time of the year. Results of this were basically the males were fine but the
females died in the tanks. We did get some eggs in the tanks before they died but
none were fertile and they did not hatch.
Results from our first freshwater attempt were not clear as we did not know if they
bred as individual pairs or as a school type fish. In the fresh water we tried one
tank with a single pair. Another tank with 2 pairs and the third tank with 4 pairs.
The first tank with the single pair had no eggs. The other 2 tanks with multiple pairs
both had some eggs. That effort was a waste but we learnt a bit and then we tried it in
salt water at a salinity of 24 – 28 ppm salt.
For our salt water test we decided to repeat the experiment but with a 250i.u.
dosage rate across the board as obviously the first test rates were too high resulting
in death, not breeding.
We repeated the test in salt water in 3 different tanks with one pair, two pairs and
three pairs. At a 250 i.u. dose rate all tanks and all females spawned 80–100% with
We will with luck breed some Bullrouts in the new hatchery tanks at Aquablue this
year so we should have juvenile bullrouts for sale late 2007.