Breakdown of Ovaj akvarij ima mnogo morskih riba.
ovaj
this (m) / ova (f), ovo (n)
imati
to have
mnogo
much, a lot of (+ genitive)
riba
fish
Questions & Answers about Ovaj akvarij ima mnogo morskih riba.
Why is it morskih riba instead of the regular plural morske ribe?
After adverbs of quantity like mnogo (many/a lot), you must use the genitive case. Since we are talking about multiple fish, both the adjective and noun are in the genitive plural. This uses the exact same grammar rule as the approximate quantity words ending in -ak that you are currently learning.
How would I say the aquarium has 'about ten' sea fish using the -ak suffix?
You would replace mnogo with desetak to get: Ovaj akvarij ima desetak morskih riba. Notice that the phrase morskih riba doesn't change at all, because words ending in -ak also require the genitive plural.
Wait, isn't riba the singular form? Why isn't it spelled differently in the genitive plural?
It looks identical to the nominative singular, but it is indeed the genitive plural! For most feminine nouns ending in -a, the genitive plural is formed by a long -a sound. In writing, it happens to be spelled exactly the same as the singular. You can tell it is plural here because of the adjective morskih and the word mnogo.
Could I use puno instead of mnogo in this sentence?
Absolutely. In everyday spoken Croatian, puno is very commonly used instead of mnogo. You could say Ovaj akvarij ima puno morskih riba and it would mean exactly the same thing, still followed by the genitive plural.