Hi, the two photos posted (2nd is actually one of my juveniles) are comparing an adult male mahachaiensis and a juvenile. Their fins become longer and the spade develops with age. So yes
, they are naturally spade tails, though I assume there is some variation where some will have more impressive spades than others.
Here is the fish (or a sibling) when a little bit older. The spade has not developed, you can see that the caudal fin has developed more length but not the point yet.
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I’ll take a photo of my adult male tomorrow so you can get a better idea of how they look when older if you’d like, I believe he is almost a year old. Please let me know if you have any other questions & I hope this helps.