What's the best way to connect up the outlet of a plastic tube so it doesn't clog?
Depending on the nature of the &quot;fountain&quot; - if it does not have small jets, then run larger pipe to it. If the output of your pump is all being driven through that tiny hose outlet, (which is my reading of what you wrote) there'a design flaw here someplace.
Otherwise, filters. You want a great deal of filter area so that it will continue to flow when partially clogged, so that you don't have to clean it too frequently. You definitely do not want the filters to pass anything small enough to clog the fountain jets, or any other part of the plumbing. You know full well it will have to catch a bunch of stuff, so make it big, which keeps the flow on any one section low. Then hose it out monthly or weekly or at whatever frequency it requires to maintain flow.