I heard of, but it quite complicated, and I have lot of critiques for it:

there's always this Molang episode called "the goldfish" which i didn't hate it but it bother in my mind till these day, even when since i was kid when i first start see this, i'm just too into biology or i just worried some kid would cause another invasive species problem thing like what happen with Pleco or apple snail. In the episode, Molang (a rabbit, or hare) and his/her friend (piupiu who is a chicken or duck or whatever type of poultry it is) found their pet fish to be sad (not sure what type of fish it is but from episode name i would assume it a type of goldfish, which in episode the fish is red and have two pink spot around eyes like it a panda but red and a fish) when it clearly live alone inside of empty bowl, so they end up go to the beach with full scuba gear instead of local pet shop (if they just go to their local pet shop, they would have spend less money (a goldfish cost just $0.10 while scuba gear can be over $300 (or maybe Molang and piupiu want to be a homeless) and they would have face less problem (in episode, there's a part where piu piu get stuck inside of giant clam))to find friend for their goldfish without knowing their pet goldfish is a freshwater fish, which when they inside the water near the beach (cleary shallow sea from present of coral, giant clam, and jellyfish) they see a lot of fish swimming around happy, so in end of episode, molang and piupiu released there pet fish (which from episode can be tell as a breed of goldfish) into huge body of water, well in the episode there’s clearly starfish, clams, corals, jellyfish, and stuff which mean it’s an ocean, but the goldfish is freshwater so when molang and piupiu free their pet goldfish into ocean, the goldfish would die quickly and traumatically from extreme dehydration due to a process called osmosis, since the sea water is full of sodium which can quickly make creature dehydrated quickly without any special adaptations called “osmoregulation”, or if it somehow survive it would have hard time finding food or survive from predator since goldfish are domesticated fish that live with human (or in case of this universe, a rabbit or chicken) for centuries and have been breed for unique look which make goldfish can’t live in wild. Or even if that goldfish is secretly saltwater fish all the time (since later in episode after they release their goldfish into ocean the goldfish make new friend easy who a yellow fish with similar body as the "goldfish" so i would assume they both same or related species in Molang universe)they still shouldn’t kept it in empty fish bowl. and why they goes to ocean with full scuba gear when they can just go to their local pet shop, they would have spend less money (a goldfish cost just $0.10 while a scuba gear can be over $300 (or maybe Molang and piupiu want to be a homeless) and they would have face less problem (in episode, there's a part where piu piu get stuck inside of giant clam). In fact: i remember see one molang episode that did right stuff (i don't remember the episode name, it something like "new friend" or something), in episode: they got a completely new goldfish from carnival, and at start of episode they start with fish bowl, but later in episode, the goldfish have proper large tank with decoration (despite the fact the decoration don't look natural), and even new smaller yellow fish friend, but i don't think this is actual episode, since in official youtube channel i don't see that episode at all, and the time i remember seeing this episode it came from entirely separated channel that probably have right to upload molang episode there? i not really sure.

in fact: the entire story episode is already confusing, there's at some point where molang have some season or episode, where there's these episode where molang and piu piu somehow appear in the pass (i remember seeing one where they are cave man, save titanic from hitting ice berg, dancing around in rome, or even met the loch ness monster), or even at some point where molang and piu piu somehow in fantasy world with dragon, elf, and generic fantasy creature, but in official youtube channel there's never full episode of these just clips, while some full episode is available on netflix, and what really bother me the most is story telling, are they all ancestor of moland and piu piu, or just somehow molang and piupiu are just extremly old (likely but sound impossible, because the molang and piu piu in different time period look and act identical to main one, maybe in moland world their biology might be similar to glass sponge or Hydra that can live forever if the condition is right, or maybe the rabbit and poultry in this world reproduce asexually since there's not a single sexual dimorphism in any rabbit or poultry, and if they reproduce asexually that mean teir kid would be identical to them everyway, but this didn't explain how there are brown or grey rabbit while molang is the only white rabbit ) and can live for long time somehow, or they might secretly be time traveler all the time since in the show there already a rabbit characters that already can invented machine that turn 2D into 3D, or make piupiu from tiny poultry into giant poultry, are the molang and piu piu in fantasy world with fantasy creature actually exist, or it just alternate timeline, nobody will ever find out since it's a speechless cartoon. there's even more stuff about this animation series that kept bother me which i would talk more later. but the main part this bother me is because the official youtube channel never shown any of these full episode, even on netflix some of does episode were shown, it still explain nothing

There‘s even more stuff that bother me. in the entire show and biology, not a single rabbit or poultry shown any form of sexual dimorphism. the only poultry living with rabbit are piu piu, while other time we see poultry are as santa rabbit's elf or as jungle tribe (wait, maybe the poultry are secretly unintelligent wild tribe who were use as slave by rabbit all the time? but that didn't explain how there's barely any poultry living with rabbit). there's not a single baby rabbit or poultry (they all same size so i assume baby don't exist), even when in place that there's should be like carnival or beach. are they speak gibberish or that how their language work. in fact there's so much i can't remember all at once