Correct terminology???

[sharkweek178]

The diagram I found names them as both ventral and pelvic fins, so take your pick which one to use

I wonder if it depends on the species. Most of the stuff I've seen treats them as synonymous but usually use the term pelvic. Maybe it's based on shape. Like the long feeler fins on gourami are called ventral. But the more fan shaped fins on other fish are pelvic. Or maybe function, as in pelvic fins assist in swimming while ventral fins are more for sensory purposes.

 

[Colin_T]

Ventral refers to the underside (belly side) if fish and dorsal refers to their back (top half of the body. You can use either name (ventral fins or pelvic fins). Ichthyologists normally use ventral, whereas the average fish keeper uses pelvic.

Adipose fin has been used to describe the second dorsal fin on tetras for over 50 years. Whether it's the correct name now I don't know. I call it an adipose fin because it's close to the tail, whereas a second dorsal fin normally starts closer to the head of the fish.

 

[CassCats]

Alright, my bad, I looked into some scientific literature and the term is indeed used for fish other than salmonids/catfish. My guess is that even though these fins are not fatty in the vast majority of tropical fish, the term "adipose" might have been applied here because they don't have the same types of fin rays as all the other fins, so they are fleshier than the others.

They need a better name if that's the case