What are Rays? and what significance do they have?
Different tail types have different amounts of rays. VT's, usually have two, as do CT's (though sometimes they can have more - up to 4 or even 8 sometimes). HM's have been know to have as many as 16 , but usually have 6 to 12. A HM with only 4 - 6 rays would most likely be classified as a delta or super delta. PK's generally have two (traditional PK's) and HMPK can again have 4-8. When you look for rays, they always start off at the base of the fin as one big ray, then branch off about 1/4 to halfway down the main ray. It's the branching you want to count. It can be tricky to see sometimes.
Here's a pictures taken off of aquabid to show you what I'm talking about, lol.
I drew in the rays to make it clearer. In example #1 you can see the clearly defined 4 rays. But in example #2 you can see where the rays spliting off and there's actually a 5th ray, bettas rays comes in two's so when this fish is finished maturing there's a good chance that he'll have 6 rays. You measure your bettas fins by the highest ray-count. So it could have a few rays with 4, and a few with two, but would still be classified as a 4-ray.
Edited by Zenandra, 02 January 2010 - 12:43 AM.