I’m trying to find a snake species that would fully utilize a 4’ x 2’ x 4’ enclosure. Nothing over 1000 dollars, nothing that can only be found wild caught, and I don’t want a brown species. Nothing against brown species, I just want something with a bit more color as most everything else I keep is brown. Also, no amazon tree boas. I’ve looked at them and their care, handled some at an expo and seen them in a friend’s collection, and something about them just puts me off. Not totally sure if there is a snake species out there like this, but figured it would be worth asking. If not, I’ll broaden my scope or maybe go for something else entirely. Also, recommendations can be anything from colubrids to pythons. No preference in regards to that. So, if anyone has any ideas, I’m all ears.
An option to consider could be a carpet python.
Oh right, I forgot about the colorful jungle carpets.
What about an albino Darwin as the stay smaller? Also the enclosure would look more impressive if it has something smaller living in it.
@garciademueller Ok so here are a few suggestions that are not necessarily arboreal but would probably utilize the enclosure you have but IMHO would fit the criteria of color:
Brazilian Rainbow Boa. If you have 1,000 to invest you could get a beautiful one
Woma Python. Again with the 1,000 you could get a really nice one.
Savu Python. More than you might want to spend but I think they are beautiful but maybe too brown?
Red Dominican Boa. I think they tend to be red?
I have seen a lot of tree boas that are quite colorful but also quite pricey.
And maybe add Burmese Pythons to the list? Or maybe too large…
Yes I forgot about that! My suggestions are probably way off……
Like @lumpy said a smaller snake may be better…… Burmese is way too big
@garciademueller I would LOVE to have this problem??? Lol! 
Lol so would I!
Brazilian rainbow boa is a no because I don’t wanna have to worry about the water situation when I go out of town. I already plan to get a woma python for a different enclosure. Savu python could be interesting, never really considered that. With the beautiful white speckling it would still be a more unique looking snake despite the brown base. Red dominican boa would be another interesting choice, I haven’t looked into them much. Tree boas are great but I don’t really have 4000 dollars to shell out for a captive bred animal. Burmese pythons are definitely too big and they’re illegal in my state so I’d be breaking several laws just to get one here, let alone keep one. So two good suggestions in there. I’ll certainly look into the savu pythons and dominican boas.
Not really a fan of morphs in general. I keep morph hognoses and plan on breeding them, but when it comes to pet only animals I try to always go for a more natural looking specimen. I want to feel like I have a real piece of nature in my house, not a little middle school diorama. So an albino carpet python isn’t really the choice for me. Not my place though to police the collections of other people. If they wanna keep pet only morphs just cause they like the way they look, to each their own.
@garciademueller Ok at least I gave you something to think about! Lol! And I CERTAINLY don’t want you to get into trouble with the law!!! 
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I’m looking at dominican boas and other Chilabothrus species, and wow, how are more people not talking about these? Absolutely stunning creatures, and so close to the US.
Then how about just a normal carpet could work for you.
I know! I would like to be able to have the space for a Dominican. I think I first saw one on LLLReptile. I think they are not appreciated as they should be looks wise but I don’t know about temperament……
Yes, I do believe some localities and subspecies of carpets could work for me.
It wasn’t a dominican boa, but I remember seeing some species of chilabothrus at the Toronto Zoo and thinking about how beautiful it was. That zoo had many beautiful species. Fiji banded iguanas, boelens pythons, retics, black breasted leaf turtles, chinese crocodile lizards. The list goes on. Definitely a zoo I’ll wanna revisit at some point.
For lots of colour and always out I would say rhino rats
If you are game for a carpet then I would advocate for bredli
Candoia bibroni are lots of fun. Mine are WC but the occasional CBB turn up. Fun thing with them is that they change colour depending on time of day
Sawu tend to be a bit more terrestrial. Also the price tag on them is ~$1500 last I checked
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Because, other than Dominicans, many are ESA/CITES and so it is a very niche community that works with them. I have also heard that getting the babies started on them is supposed to be rough.
This might fit you requirements, green or blue ribbon snake.
What about a Baron’s Racer? I know very little about them, and now that I think about it, I’m not even sure if they’re arboreal (think I saw a picture once of one in a tree…? I know, super thorough research on my part ), but they’re certainly colourful, unique-looking animals.
I know some rat snakes have arboreal or semi-arboreal tendencies, though I’m not super knowledgeable about rat snakes generally, so I can’t suggest a specific species.
I second to suggestion of some sort of carpet python. I know you’re not into morphs, but there are several different species to choose from, offering an array of sizes and appearances even if you stick to wild types. They’re all really beautiful, so it would be hard to go wrong.
EDIT: Baron’s racers are indeed arboreal.