Pretty tank.
It looks quiet. Is it the new norm or just one of rare peaceful moments?
Eupterus is a solitary, territorial riverine synodontis. They do not form long-term male-female pairs in the wild. They come together only for short term for mating. So what you had before was rather an exception and a testament to their adaptability, which is variable.
It is more natural than not for them to be assertive and defend their territory. It is also natural for them to establish a pecking order and enforce it, if they have to. That could easily be what was happening when you introduced the new syno. After the initial period, this usually subsides to a quite tolerable level.
Gender surely plays a role with males being more competitive among themselves than females. But since this whole thing of having more than one syno in one tank is an unnatural situation, it's hard to predict what exactly will happen. Too many variables with tank size being one of many. Gender, tank size, fish size and age, decor, water temp, pH, chemistry, the order of introduction into the tank, tank mates, hiding spots, current, lighting, diet, fish character, health, etc. all appear to have a bearing on such interactions.
You yourself have just witnessed that the extrapolation of the relationship of two synos in one given tank is not straightforward at all. This and similar accounts abound. Intra-tank (like your case) and inter-tank.
So, in short, based on what we know about their life in the wild, a eupterus should be the happiest with no kin in sight. The "sulking" you observed was in all likelihood you anthropomorphizing your eupterus
Changes in the stock bring about changes in behavior and we tend to interpret them from our, human point of view.
I'm not saying that's what was happening but in one extreme illustrative example, one may imagine a keeper mistakenly taking all the swimming around and activity for happiness and fun while it is conducted out of anxiety or similar impulses or rather instincts; and when the source of that anxiety / irritation is removed, the ensuing peace could be misinterpreted as sadness, while the fish finally got some peace, quiet, and serenity. Just food for thought.
It looks quiet. Is it the new norm or just one of rare peaceful moments?
Eupterus is a solitary, territorial riverine synodontis. They do not form long-term male-female pairs in the wild. They come together only for short term for mating. So what you had before was rather an exception and a testament to their adaptability, which is variable.
It is more natural than not for them to be assertive and defend their territory. It is also natural for them to establish a pecking order and enforce it, if they have to. That could easily be what was happening when you introduced the new syno. After the initial period, this usually subsides to a quite tolerable level.
Gender surely plays a role with males being more competitive among themselves than females. But since this whole thing of having more than one syno in one tank is an unnatural situation, it's hard to predict what exactly will happen. Too many variables with tank size being one of many. Gender, tank size, fish size and age, decor, water temp, pH, chemistry, the order of introduction into the tank, tank mates, hiding spots, current, lighting, diet, fish character, health, etc. all appear to have a bearing on such interactions.
You yourself have just witnessed that the extrapolation of the relationship of two synos in one given tank is not straightforward at all. This and similar accounts abound. Intra-tank (like your case) and inter-tank.
So, in short, based on what we know about their life in the wild, a eupterus should be the happiest with no kin in sight. The "sulking" you observed was in all likelihood you anthropomorphizing your eupterus
Changes in the stock bring about changes in behavior and we tend to interpret them from our, human point of view.I'm not saying that's what was happening but in one extreme illustrative example, one may imagine a keeper mistakenly taking all the swimming around and activity for happiness and fun while it is conducted out of anxiety or similar impulses or rather instincts; and when the source of that anxiety / irritation is removed, the ensuing peace could be misinterpreted as sadness, while the fish finally got some peace, quiet, and serenity. Just food for thought.
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