Common names are easier to learn than sicentific names, but on the other hand, scientific names have several advantages:
1. They are the same all over the world. No matter if you are in the US, England, China or Australia, the name for a
Hypancistrus zebra is the same - and it means the same species of fish in all places too!!
2. There is only ONE (valid) scientific name for a particular species. [Now, let's not get into a discussion about who decides which ones are valid and which aren't, please

]. Older names are kept on record as "synonyms", so if you find your fish in an older book, using an old name, it can still be "traced" to the new name now. [Names change because of further research - for example what was previously considered two different species will become one species, and the oldest name should then be used, with the "newer" one being a synonym. Or a genus (small group of fish with similar traits) may either split into multiple new genera, or be merged with another genera (e.g. the genus Cochliodon is, at least by some, considered a synonym with Hypostomus, so your L137 belongs, if we follow this, to the genus Hypostomus, whilst older literature will call it Cochliodon).
Sorry, that became quite long and complex - feel free to accept the shorter version:
Scientific names are more precise and internationally accepted. Common names are often used for more than one species of fish, and sometimes not the same in different parts of the world. '
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Mats