so nice that your Pleco aggression problem has been worked out and that their health is much better too! I love how much you care about your fish Danny.
Happened to pull up youtube and see you just posted - yay for your zebras! So glad to hear they are healthy and happy and your methods have worked. I went to a fish club auction about 2 hrs from my house this past weekend. No one had any zebras they were selling, but I did bring back a stunning guppy trio of ginga sulphureus. There were some lovely corydora groups I bid on, but all were auctioned higher than my price range:) Lots of cichlids, quite a variety of fish, hardscape supplies, tools, and more. And my favorite - lots and lots of plants in the auction! I brought back 12 plants for my tanks.
Have you thought about black pvc pipes which you can get in different sizes? You can always add a cap on the end to close one end off. I also found ceramic logs in my pet stores that workers. I bred bristlenose plecos inadvertently by adding the ceramic hollow logs in and I had 1 male and two females.
Do you have any locals who do pottery? You may be able to help them make a bit of out of tourist season earnings if you give them the idea of making pleco caves. I had a fish keeper aquaintance once who also did pottery, who made pleco caves and a few other "fishy" things. Cost a little more to buy from her, but it supported her hobby and we always had supplies. Maybe an idea of import can be a little tricky or expensive where you are? All the best!