I found this neat map of all licensed Polish zoos. Very handy. BTW it even contained 2 establishments I had no idea existed till now. It was created by Zoo Lesne Zacisze (that I have seen referenced as the best one among private zoos in Poland) earlier this year so it should depict curent state.
This gives us 25 zoos (26 if I count Poznan old zoo and new zoo separatedly).
I will type them down and add attendance info in case I have found any for year 2022.
1. Zoo Wroclaw - 1 710 000
2. Zoo Leczna
3. Zoo Lubin - approximately 500 000 (entry is free of charge)
4. Zoo Bydgoszcz
5. Zoo Torun
6. Zoo Zamosc - 210 000
7. Zoo Wojciechow
8. Zoo Lodz - 1 000 000 (they broke 1 mio few days before year end)
9. Zoo Borysew - app 80 000
10. Zoo Krakow - 539 190
11. Zoo Plock - 199 505
12. Zoo Warszawa - "almost 1 000 000"
13. Zoo Opole - 288 000
14. Zoo Bialystock
15. Akwarium Gdynia - app 500 000
16. Zoo Gdansk - 519 198
17. CANPOL Czluchow (free of charge)
18. Zoo Charlotta
19. Zoo Chorzow (Katowice) - 480 000
20. Park Ustron
21. Mini zoo Sosnowiec (free of charge)
22. Zoo Lesne Zacisze
23. Zoo Kadzidlowo
24. Zoo Poznan (Stare and Nowe) - app 700 000
25. Zoo Nowy Tomysl
None of listed zoos that lack attendance info should have more than 500k. Most of those places have probably around 100k or less.
The list lacks Fokarium Hel (seal rescue station) that had 500 000 visitors in year 2014, but I lack newer info. Czech tourists in summer 2023 complained about 1 hour qeueing time to buy a ticket so I conclude it probably still has good attendance.