There has been some discussion on the accuracy of science journalism. I address that here due to the amount of time I already dumped into this current investigation.
Of many, an initial curiosity relates the claims in the article to the actual findings and conclusion of the original scientific study. This tiny query, diligently pursued, led to a reasonable chronology of the story: do fish count?
Quantity discrimination in female mosquitofish.
Fish can count to four--but no higher
Do fish count? Spontaneous discrimination of quantity in female mosquitofish.
Use of Numbers by Fish
Fish Can Count, Study Finds
Can angelfish (Pterophyllum scalare) count? Discrimination between different shoal sizes follows Weber’s law
Ontogeny of Numerical Abilities in Fish
Large Number Discrimination by Mosquitofish
Fish as Good as College Students in Numbers Test