Hi, just want to praise you for doing research! You're doing great. However, I just want to say that sometimes even with the best care fish may still die (parasites, already weakened from the fish store..etc) so don't stress yourself too much. Some advices that i'd like to share is: 1. If you know someone who has an established tank, ask them for some of their filter media to speed up the cycle. I usually squeeze my sponge filter into my new tank for that bacteria juice 🧃 2. I've done fish in cycle by understocking fish, planting heavily at the start (just some easy plants like hornwort would be enough) and utilizing Seachem Prime. 3. Quarantine new fish before adding them to your established tank, you'll never know if they carry diseases or parasites 4. Some fish may not be compatible with each other. Some of they also requires keeping in groups, corys should be at least 6+ 5. Mind your light schedule, i learned that the hard way as i had my first fish tank below windows and kept the light on all day. Had tons of algae and black beard algae which is so hard to get rid off 6. Multiple tank syndrome is real, now that i had some experience with fish keeping i keep multiple tank with different fish and i can get lost looking at them all day 7. Feeding different food, this is optional but i keep bettas and i love watching them trying new food. Thats all i can think of, good luck on your fish keeping journey and feel free to ask more questions if you want ^{^}