Several days ago, I was viewing a poster of sorts with but two inherent flaws.
To the left, we see a depiction of a coral reef which appears to be thriving and, by extension, teeming with marine life. Automatically, one notices species from the Paracanthurus, Amphiprion, and Chaetodon genera. All seems well, thus far, we may agree. However, look more closely, and you pick out Pterophyllum scalare floating jovially by. Look towards the right-most corner of the image, and you may also note Symphysodon aequifasciatus cuddling into some anemones. This genuinely upsets me, as both of the aforementioned are widely-known freshwater species arising from the Amazon Basin. Their being introduced to a saltwater community is entirely impossible.
That said, justification for this error may exist in the case of P. scalare. To introduce the ambiguous component of this posting, the aforementioned cichlid’s common name is “angelfish”. However, members of the family Pomacanthidae (this containing a large quantity of marine species) are also colloquially termed “angelfish”. Thus, a person wishing to locate an angelfish species to utilize in just such a display might be faced with both options and may, although unknowingly, insert a freshwater fish into a perilous albeit scenic seascape.