I like it! I just noticed a few typos, I will list them and this constructive criticism, I'm not trying to nitpick or anything!
In the first sentence, I think you meant 'are known' instead of 'a known' (I'm sure it's just a typo!) and 'elaborant' is actually spelled 'elaborate'. I think the parenthesis is probably unnecessary, as you already stated that bettas need 2.5 'per fish.' It will flow better without the added statement and you've already stated the needed info. In the sentence after, you just need an 'and' between 'fish' and 'need.' In the last sentence or the next one you write, I would describe briefly how to make sure your decor is safe. Overall, I think It's a great start to your article and I can't wait to see the rest!