Spawning the Panaque sp. nigrolineatus L190 ?
by George J. Reclos
This is a very strange article for a number of reasons. To start with, I would like to tell you that all was the result of careful planning or a strict protocol like the one described in the excellent article of Francesco on his attempt to spawn members of the Ancsistrus genus. But it wasn't. Claiming to be an expert in catfishes is as far from truth as it can be. Pretending to have the ideal water conditions (soft water, low pH etc.) would be a lie too. Moreover, the tank my Panaque L190 (with all the reservations stated in the "Royal Panaque group" article - also by Francesco - as far as correct classification is concerned) are housed in my 1300 liter tank with many other catfishes and Madagascan cichlids, definitely not the best place they would choose to spawn. However, to my surprise, they did. Therefore, this article can only serve two purposes. First, report (perhaps for the first time) the successful spawning of the Royal pleco in captivity. Second, give you the data (as much as I can think of) and let the experts decide which were the factors that a) triggered spawning and b) allowed those catfishes to accomplish their task. Let me state, right from the start, that any feedback is welcomed, will be added in this article and full credit will be given to the sender.
The tank has a pH fluctuating between 7.6 and 7.8, a GH of 12 and KH of 14. Water changes are performed every week (about 80% of the total water volume) and the temperature during those changes falls gradually from 26 to 22oC (takes an hour or so) and then climbs back to 26 in a couple of hours. The tank bottom is sand and there is a lot of bogwood and vine tree wood in it. Finally, there are many Vallisneria plants. As I have confessed many times in the past, I don't vacuum the bottom. Most of the cichlids I keep are sand shifters, the Botia modesta too and I have three Akanthopsis choirorhynchus which literally live in the sand. You can see a picture and detailed description of the tank here. Each time the fish eat, they shift the bottom and there are a lot of debris that are suspended in the water for an hour or so but I like it as it seems far more natural than a sterile, always shining substrate. I have seen what happens in rivers, lakes and the sea and this "sterile" bottom doesn't exist there therefore there is no reason to fight for it in my tanks. The presence of the catfishes guarantees that no uneaten food remains in the tank (since I never feed them at night).
Although I don't feed them still they eat a lot. My Panaque sp. have managed to consume about 20 Kg of wine tree wood during the last year. I mean, they literally ate it. There is nothing left of it anymore. Initially I added about 35 Kg of vine tree wood and now I can barely see some of it in the tank which - naturally - has changed a lot since then. I am going to prepare another batch of this type of wood soon (perhaps another 40 Kg) to create some hiding places for everybody in the tank. The main issue is that what goes in has to come out, too, so all those kilograms of wood have become wood debris which - due to the water movement - have formed a huge pile in the dead spot of the tank, just below the outlet of the main pump. As you can see in the photo below, the pile is approximately 50 cm long, 30 cm wide and 30 cm high at its tallest point. The first question that crossed my mind when I saw the two little Panaque in my filter compartment was where did the parents laid their eggs. It couldn't be in the open space or any other element in the tank since the other catfishes would have eaten them on the spot. So they had managed to hide them somewhere. After searching the whole tank many times, Johnny (my son for those who don't know him) called me to see a "strange construction" in the debris pile.
Indeed, after examining the pile for a long time it became apparent that something had created a series of tunnels in it. The tunnels run through the whole body of the pile and at some points came up to the glass. Traces of sand probably indicate that the fish (?) entered the debris pile from the left side (as shown in the picture - see the sand layer over the debris at this point) went over the Vallisneria roots and then started building the tunnel. It is amazing to know that there has been a great deal of activity going on in this tank without us ever noticing it.
This is a close up of the end of one of those tunnels taken from the glass side of course. No matter how much we tried, it is impossible to see what is in there or which direction it follows. All we can say is that it is quite long since the other side is not visible despite the use of diving torches. The diameter of this "hole" is approximately 2.5 cm (1 inch) and is kept in place by something like a "glue". I can't guarantee that this tunnels were made by the Panaque or that they were used as the actual spawning site. It may well be a coincidence. All I am doing in this report is to share the data hoping that light will be shed by other, more knowledgeable catfish lovers.
We managed to find two of the small catfishes in the filter compartment. They may be significantly more of them in there but only once did we have the chance to see two of them at the same time on the glass of the filter compartment. Of course the compartment is quite large and we can only see part of one glass. The large head is typical of the Panaque genus (at least of the Panaque that I keep in this tank) while the white band in the tail suggests that this is Panaque sp. nigrolineatus L190. Needless to say, this is just a guess, hence the question mark in the title. The size of both fish is about 1 cm (you can see the size of the fish compared to the blue biospherel behind it). It is really difficult to see them and almost impossible to get a better picture of them. There are 15 mm of glass in front of the camera, 20 cm of water and then another 8 mm of glass between the fish and the camera, not to mention that you have to shoot at an angle. The first time I saw them was during a water change while changing the filter floss and I thought I had some kind of leaches in my tank ! It took me 24 hours to find it again and show it to my son. It seems that some of the fry managed to get in the filter compartment in which the larger fish have no access so they were allowed to grow while the rest of the brood, which stayed in the main tank, was probably eaten by the other catfishes or the cichlids. Although we search for them on a daily basis, we can only see them every 3-4 days. Netting them is out of the question. I never imagined catfish can be so quick. Twenty days later it seems it gained some size since it was measured (as accurately as we could) to be 1.5 cm (total length of course.. ).
Panaque sp. are truly territorial fish and do not like to see conspecifics in their close environment. However, we have repeatedly watched the two individuals shown in this photo sharing the same wood or rest under the same branch in very close proximity. My knowledge on catfishes is quite limited so I can't tell if this is a pair or not. All I know is that they both chase the third individual every time he/she comes closer than 20 cm. The fish shown in the pictures are sized 15 cm (tail included) and have been staying in this tank for more than a year. If I am allowed to make some speculations, I would focus on three elements which may have attributed to this "accidental" success. First come the large water changed which may have given the fish a stable and pollutant free environment. In the Amazon basin water flow is exceptionally high and most of the species that come from this area are not accustomed to pollutants. It is true that I have never seen a detectable amount of nitrates in this tank. The second element could be the presence of the vine tree wood. As opposed to bogwood, this type of wood is soft and is easier eaten by the Panaque. This species heavily relies on wood which forms the main part of its diet therefore the presence of a large amount of easily "chewed" wood might be beneficial (something like offering "live" food for conditioning cichlids). The fact that they can "eat" a small branch in less than two days says a lot. Last, but definitely not least, the fact that I never vacuum my tanks unless I see uneaten food, may be a crucial factor, too. The debris pile might be the final pixel in this picture since it may have allowed the animals to lay their eggs in a safe space which guaranteed - at least - survival till hatching. Of course, these are mere speculations. This "article" is not finished yet. If I get any additional information from other hobbyists, comments or corrections, I will be happy to include them.
As I was writing this article I shared the title with Francesco and Frank. Frank told me that a Belgian hobbyist, Johan Melis, managed to breed his 6 year old Panaque sp. and he currently has 60 fry thriving in the strong current of his filter compartment. Unfortunately, he doesn't have an e-mail to contact him, therefore the exchange of information with him is not possible for the time being. It seems that filter compartments are their preferred place for two reasons: they avoid being prayed upon and they have a strong current of oxygen rich water. If Frank manages to bring us into contact, I will be more than happy to present his story, too.