"The tree has been spread widely by humans and the native range is uncertain. It has long been naturalised in a broad belt extending from Africa to Northern Australia and New Guinea through Southeast Asia and Micronesia into the Indian Subcontinent. More recently the plant has been introduced to parts of the Americas."
Betta fins are unlike color - there is little difference in color enhancement due to different care. Where as fins are highly dependent on general care and water chemistry. We know that they need certain parameters like temp, hardness, pH, etc. But it's difficult for us to know it's actual chemistry and often neglect it since, health wise, most bettas are tolerant towards these chemistry. I have had perfectly good pairs of HM with 8 rays produced only deltas and super deltas because I used 100% rain water since day 1 to adult - regardless of food and exercise.
Food also plays a big role in fin development. Wormy foods will make fry grow faster but will, to some extent hold off fin development. Thus body may look bigger but fins may look juvie. Since I feed a lot of tubifex, most of my collection has smaller fins compared to others. An equal and steady growth between body and fin is desired. Many claim that feeding BBS - daphnia - mosq. larva during their growth results in slower but ideal growth; giving them full fins at an early age.. Boosting growth can be achieved through massive water change daily or slow running water in grow out ponds.
Then there is general care - regular flaring at least 15 minutes daily as early as 2 months of age helps widen their webbing. Constant flaring is not good because it either makes them uninterested or stressed thus they won't spread their fins. Being jarred early will also reduce growth, giving fins a better chance of growing.
All of the above take part in fin development, whether individually or combined. If given the right food and care still gives them smaller fins, check you water chemistry.... (I don't know the ideal water chemistry) .... all I know is that spring water in one area may have contrasting chemistry compared to an area 3 miles away.
BTW, IAL should only be used mildly for long fins - except CT. Too much IAL is said can cause web shrinkage(?) or folding. SO when you're using IAL for HM, only make the water yellowish. Don't make it dark brown on a regular basis. If possible don't use it at all if you're not showing your betta........ again water chemistry.
Actually it's not that scary. That's only "behind the scene" that most people don't bother to look into. In real life it's much easier. If you're working with HM or PK, regular and standard tap water is adequate. Simply feed more shrimp like foods - bbs, daphnia, ML, minced shrimp, etc. Don't feed too much wormy food - tubifex, black worm, blood worm, etc. Jar since 2 months regardless of aggression and exercise regularly (this is one of those daily hobby activities - flare them and appreciate their beauty)
Breeding is one of my goals eventually, in a year or two. Yellows or oranges would be fun for me, if I managed to get a nice pair, HM or PK. Good to know all this.
When changing water in the jars (daily I'm assuming) do you take the fish out or drain it so the fish just barely stays inside?
I take them out and wipe/scrub everything. It would be better if you had 2 for every betta (if possible) - No matter how you scrub, there will always be leftover bacteria. So it's best to move them to another container (I use 2 ltr drink bottles cut 2/3 - 1/2, half gallons, and 1g depending on betta size) and dry the previous one for later use ..... this is only me. I know others don't do this.
First I pour most of the water out so I know I can pour the betta (it won't jump out) into my hand/net. This way I will never have to chase them around. Then put them in the new water and tank. Clean the previous tank and let it dry. I usually water change everyday and change tanks every 2-3 days.
Looking forward to reading your future spawn logs....