Shane's World Right Arrow Reproduction Right Arrow Breeding Pseudacanthicus spinosus • Article © Mingxin Guo, uploaded December 02, 2009


1. Male

The start of such wonderful species
Pseudacanthicus spinosus is a very interesting species that comes in many different variants in terms of forms of coloration, spots and markings. Not to mention conferring species, it comprises of 3 different L-numbers, L96, L160 and L375. However, none other than the L160 came in to Singapore as a shipment before, making them even harder to obtain. Moreover, the fact that L96 and L160 are both classified together as the same fish in most publications makes me interested to find out more about them. This is why I’ve been solely focused on them since 2007. However, my love for Pseudacanthicus started way back in early 2004 when I first started this hobby. I have tried keeping almost all of the Pseudacanthicus species. Yet nothing beats concentrating on P. spinosus.

L096 was the one I was dreaming for, yet none of them came in shipments, the only information that I got hold was that they do come in as containment in L160 P. spinosus shipments. So from then on, whenever there was any shipment, I would try my luck to spot the difference in them.
As time passed and with their enormous growth rate at 3 to 5 inches a year, I have no choice but to concentrate solely on them. Having kept most of species before, breeding them was the next step in my hobby as I have more than 16 of them at various sizes, ranging from 4 to 13 inches. To date, I have had three spawns from the same parents and I will try to give an account of the first spawn. What I write is my learning process.

It begins in May 2009
It all happens by coincidence when I have send two fishes for a pleco competition at Aquarama, one of Asia’s biggest international ornamental fish and accessories exhibitions for the aquatic fish industry and its related sectors. The cave that measures 3.5” by 3.5” by 10” was occupied by one of them became vacant and this gave a wonderful opportunity for one of the other males to trap his mate inside. The trapping was not consistent, after a day or two; the female would escape out of the cave. However, the next moment, the male would be back, trapping her in the cave again. A possible reason is the number of occupants in the tank. I have 14 of the same species in a 180cm by 60cm by 60cm tank.


2. Male trapping female in cave.

31st May 2009
Today, I brought back the two fishes I had sent for competition earlier. When they first entered the tank, they seem lost and appear to target the trapping male in the cave. Fearing that it might affect their activities, I removed the trapping pair into another smaller tank solely by themselves. Furthermore, I introduced another female, whom he had trapped earlier before so that just in case, this current female failed, he still has another option with the other female. The temperature seemed slightly higher as compared to the larger tank, so I had decided to do a massive water change to bring down the temperature.

1st June 2009 The next morning, everything seems normal. The male is still inside the cave. So I presume that everything is still under control. However, at night I’m surprised. I have found a huge bunch of eggs, not inside the cave but outside in the tank. I quickly transferred them into a floating hatchery with an air stone to keep them well-ventilated.

2nd June 2009 - day 01
Some bad eggs were found in the hatchery, turning from clear-transparent yellow to mustard. These could possibly be those unfertilized ones. They are still in a ball, which makes cleaning the egg mass a difficult task for me. I have to use a pipette to remove those bad ones one by one, trying not the affect those surrounding it.

4th June 2009 - day 03
Due to a technical problem, the air stone fails to provide aeration to the hatchery. More than half of the eggs have turned opaque. Instead of clearing away those, I tried to savage those unaffected ones. Those with their yolk burst are causing the water to turn bad and cause the surface to be covered with a thin layer of protein substance. I have to do a partial water change and transferred those possible unaffected ones back into the same hatchery after it has been cleaned. I have a balance of 34 eggs after the salvage operation. They have their spine formed inside the shell. I could see that their eyes are formed too.

5th June 2009 - day 04
At 0900hrs, 28 of them were left and most of them have hatched from their shell. However, by the night I was down to 21 of them.

8th June 2009 - day 07
Casualties had dropped to 17 wrigglers. Not only their eyes and mouth have developed, I have noticed that their pectoral, dorsal and ventral fins have started to form. Some of them have “air spaces” inside their egg sag and these are the ones that never make it alive. I have never encountered or heard anything like this before. It might be caused by the incident on the 3rd day.

10th June 2009 - day 09.
As expected, one of the deformed wrigglers with a "space" in the yolk, departed. In the morning, it was looking normal, but when I noticed it in the night, what was left was just the body; the yolk was nowhere to be found.

19th June 2009, Day 18.
After a week, I am left with 9 wrigglers. Some of them, who did not make it with the rest, were developing much slower. The remaining ones are still not eating solid food, even when I had introduced baby pellets for them. However, ever since I have added a piece of small driftwood into the tank, they seem to have started chewing on them. Ironically, they don’t seem to hide under the driftwood for shade, they still prefer to cluster together in a group.

1st July 2009, Day 30.
Unfortunately, I have am down to 5 wrigglers, out of the 9 that I had at Day 20. It seems like a sudden death, where there aren’t any drastic changes in the water parameter. Possibly that they were the weaker ones that did not managed to survive, given that my air pump stop functioning on Day 3 that have caused more than 50% of the eggs to turn bad. They started their solid food feeding on Day 24, feeding on Hikari micro wafer. So far, their response to the food is very good and they are not shy to come out in the open to eat. Moreover, I have added some moss inside for them. They may get to eat some of the micro-organism on the moss itself.

16th July 2009, Day 45
The 5 fry that were left from the first spawn, grew to be close to 2cm after I took them out for measurement and photography.

16th August 2009, Day 75.
Today, 3 of them reached 2.5cm TL (1inch) since birth. However, the remaining 2 seemed to be at 2 cm or 2.25cm. These growth rates are very much slower than the rest. At close range, I had noticed that their body markings have developed with irregular spotting. None of the 5 pieces looks the same to one another.

1st September 2009, Day 90.
These fry have begun to colour up with their tails starting to have a pale orange tint.

22nd October 2009, Day 141
I have transferred the 5 fry into a much bigger tank. They have grown noticeably and their colouration has undoubtedly become brighter. Size-wise were from 2” to 2.25”. My second batch came three months after the first spawn in September. The first spawn was a learning phrase for me; I managed not to repeat those mistakes I had made earlier and the sight of the “space inside the yolk” never happened again.

Sexing: Male and Female
The male is currently 11” TL while the female is at 8.5”. Most publications state that the difference is in the size of the pectoral and, yes, I would agree. But what size is consider big and what size is smaller? To what I have observed in this species, the male has a longer pectoral, thus the bigger in size. Using the pelvic fin as a guide, the male’s pectoral will cover the most a quarter of the pelvic fins, while the female’s never or just reaches the pelvic. This is depending on how gravid the female is.

This is the most accurate data observed in this species although other publications states that the size of the dorsal, shape of the head and the odontodal growth on the pectoral are other criteria to look out for but these are not consistent in most of the Pseudacanthicus species. Another indicator is the appearance of the fish, the spots and markings also play a part. Males tend to have a very distinct markings and spots while the females seem to be very patchy and faded. Reason being, males tend to be more brightly coloured than females. Thus, the spots are more clearly defined. These are some observations that I have concluded for this species. It may not be applicable to other congeners.

Egg clutch
3. Egg clutch

Six day old fry
4. Five day old fry

Nine day old fry
5. Fry with yolk sac problem

Twelve day old fry
6. Ten day old fry

Fifteen day old fry
7. Thirty day old fry

Nineteen day old fry
8. Seventy day old fry

Twenty three day old fry
9. Three month old juveniles

   

Breeding Conditions and Signs
I have tried many ways to pair them up and one of the ways is to let them choose their partners inside a colony tank. It may seem not too obvious until trapping occurs but there are hints that might prove that a pairing up is in play. In a colony tank, if any females are spotted with bite marks on the back, it is a good sign! This has shown that somehow or rather, a male has tried to trap her in the cave but is not successful.

Once I have confirmed a possible pairing, I would transfer them into a tank by themselves. Additionally, I would also introduce a smaller female inside. This would induce the male to work harder while the female gets jealous with a new “intruder” and tries to pair up quickly with the male. One interesting encounter that I have observed is that the males will only challenge among themselves, leaving the female alone. While that same goes to the females as well. Having two males instead of female inside, is a big no-no. Two of them will be challenging each other until one gets wounded and retreat while the winner gets too tired or worse, wounded or too weak to try trapping the female. Thus, a smaller size female would be a better choice.

Here in Singapore, my water changes are always done when the rain comes. The temperature will be much lower as compared to the rest of the day. Although here, we do not have four seasons that give us low temperature water throughout, we substitute this with high volume water change to bring the temperature down. A drop in a few degrees might actually helps to induce the pair to spawn when they are ready. I am not sure about atmospheric pressure, but I do think that it somehow plays a role in it too.
When the male is ready, he would occupy the cave all day. He would sway his tail to attract the female, signalling her that he is ready. Alternatively, he would try to chase her around and hope that she will hide inside the cave, which makes it easier for him to trap her. However, if the male is not ready, yet the female could not wait any longer, she would try ramming herself into the cave, with the male inside. It is an indication that the male is either not interested in her or is not ready. When they are both willing parties, the female will not retaliate when the male tries to trap her. In fact, she will show some indications, like swapping her tail in front of the male, as a positive indication too.

So to end off, I hope everyone will enjoy this experience of mine and perhaps share some of my passion for these interesting fishes.


There is further information on this species on the Cat-eLog page.

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