As a small business owner I have to say that the fact hat the Seaquarium owes money to vendors and is taking a long time to pay them, past terms, is very common and is probably being made a larger issue on these forums that it really should be. It is common in general business as well as with zoos. I used to do a fair amount of work with a large zoo and they were always slow payers.
While likely true, they at the very least shouldn't be in default to the county on their loan. The reported lack of communication is probably not helping matters, it feels problematic that multiple vendors are coming forwards with concerns about not being paid.
The real issues are the clear animal care concerns,
Worth noting in my opinion that some of the unpaid vendors are listed to include engineers, pest control, and water filtration - the latter two being a significant part of animal care. If financial issues are also the reason for the lack of veterinary staff and behind the citation for being understaffed in general, then I'd argue the finances are as much a root problem of the poor animal care. And as the article mentions, this is a company that does business in eight countries - its not just a local struggling aquarium, it's part of a much bigger parent company. Less reason that it should be currently in default.