They always stay at the water surface, and are completely helpless against anything approaching from below. Only thing they can do is to jump (which doesn't work well in covered tanks, and would most likely be deadly in uncovered ones).
Since they are better looking up than down, I think in nature the extensions could help them judge when they swim into areas that become too shallow. They might help them to stay anchored between plants in rivers where they would otherwise drift around (they don't like water movement). They could also confuse predators and make it more difficult to spot them, you know, like camouflage used by moths/tigers/snakes etc.
Almost 5 years ago I started this thread, so here we are, still together, celebrating about 10 years of ABF life!
She is still as happy as always, you can tell by her smile. Even though her eyes became a bit clouded over the years, she is still quick. If I drop an insect into the tank just right, it ends up in her mouth at the same moment that it touches the water surface.
This is the male, from a low angle. He was taking a sunbath or something... sitting on top of a Bolbitis leaf with half of his body out of the water. Silly critters.
Such a good looking fish and with her cataracts, it makes it all the more endearing. Congratulations on making a decade with Mula! How often are you feeding her now? And too cute on the boy. I love the sun bathing. My shrimp love to do the same thing, but it is hilarious to see a fish that size doing that.
Without Algae, death of mankind would be inevitable.