How many what should a male have? Tail rings?
There is no difference between males and females regarding tail rings. The only difference will be that the male pouch develops behind the anal fin.
Tail rings I find are fairly consistent within a batch from specific parentage, but can be different from other parentage lines, especially if sourced from a different location originally.
From the above link I gave you, for H. kuda:
Maximum recorded adult height: 17 cm2
Trunk rings: 11
Tail rings: 36 (34"“38)
HL/SnL: 2.3 (2.0"“2.6)
Rings supporting dorsal fin: 2 trunk rings and 1 tail ring
Dorsal fin rays: 17 (17"“18)
Pectoral fin rays: 16 (15"“18)
Coronet: Low to medium-height, rounded, overhanging at the back, often with a cup-like depression in
the top; sometimes with broad flanges; not spiny
Spines: Low, rounded bumps only
Other distinctive characteristics: Deep head; deep body; thick snout
Colour/pattern: Often totally black with a grainy texture; alternatively pale yellow or cream with fairly
large, dark spots (especially females); may be sandy coloured, blending in with surroundings
Now, as tail rings are not definitive because they can have varying numbers that also are in the range of other seahorses, you have to go by all the other characteristics that may be different than other seahorses such as the coronet size, height, shape, direction, and, when mature enough, to compare the head, snout and body size, shaping and depth.
