Hi, all. Does anyone have any familiarity with breeding/courtship/territorial behavior in the Convict Blenny/Engineer Goby (Pholidichthys leucotaenia). I have a pair in my tank and am intrigued by some recent behavioral changes.
Shortly after introducing these fish into my tank, it was clear that they were not getting along. One had gotten slightly larger than the other with the smaller one appearing to get more and more "beat up" as time went on. Eventually, the larger chewed the caudal fin down to the caudal peduncle resulting in the eventual loss of the caudal fin. That's how badly these two were fighting. They would even stay on opposite sides of the tank.
Now, the fish are about 7 or 8 months old (at least) and their behavior has changed. These two are frequently seen sharing the same side of the tank. They often criss/cross with eachother with no aggression. They have also stopped any aggressive behavior towards eachother at feedings. More interesting than that is the head shaking that the smaller one does when the larger one comes close. It will stick its head out of its burrow and make a series of short, rapid up and down head shakes. It doesn't do it all the time and the action does not seem to result in any aggressive behavior by either fish. In fact, they tend to cross bodies with one another and swim in and out of eachother's burrows afterwards. I have never seen the larger fish do this head shaking behavior. In response to the head shaking, the larger one will somethimes open its mouth wide and "mouth" the body of the smaller one. The "mouthing" does not appear to be biting or nipping and the smaller fish does not seem to be in any rush to get away or to be irritated by it at all.
So, what the heck is going on? Do I have a male and female? Is the smaller one a male and is he showing some sort of precursor to mating behavior? Am I going to have to prepare for a batch of baby convicts or is this some sort of territorial display not related to mating?
Shortly after introducing these fish into my tank, it was clear that they were not getting along. One had gotten slightly larger than the other with the smaller one appearing to get more and more "beat up" as time went on. Eventually, the larger chewed the caudal fin down to the caudal peduncle resulting in the eventual loss of the caudal fin. That's how badly these two were fighting. They would even stay on opposite sides of the tank.
Now, the fish are about 7 or 8 months old (at least) and their behavior has changed. These two are frequently seen sharing the same side of the tank. They often criss/cross with eachother with no aggression. They have also stopped any aggressive behavior towards eachother at feedings. More interesting than that is the head shaking that the smaller one does when the larger one comes close. It will stick its head out of its burrow and make a series of short, rapid up and down head shakes. It doesn't do it all the time and the action does not seem to result in any aggressive behavior by either fish. In fact, they tend to cross bodies with one another and swim in and out of eachother's burrows afterwards. I have never seen the larger fish do this head shaking behavior. In response to the head shaking, the larger one will somethimes open its mouth wide and "mouth" the body of the smaller one. The "mouthing" does not appear to be biting or nipping and the smaller fish does not seem to be in any rush to get away or to be irritated by it at all.
So, what the heck is going on? Do I have a male and female? Is the smaller one a male and is he showing some sort of precursor to mating behavior? Am I going to have to prepare for a batch of baby convicts or is this some sort of territorial display not related to mating?
