10 most common mistakes new aquarists make + how to avoid them.
Adding fish before the tank cycles = ammonia poisoning. ALWAYS cycle first; takes 2-6 weeks.
You see a beautiful fish, you buy it - 2 weeks later it is dead. Always research adult size + parameters BEFORE buying.
Tanks pushed past the bio-load capacity = parameter swings + disease. Use the stocking calculator.
One unquarantined fish brings velvet/ich/flukes - wipes out the entire display in days. Always QT new fish 21-30 days.
Chlorine + chloramine kills the bio-filter. Always use Prime/dechlorinator OR RODI.
Replacing all filter media + scrubbing rock = removing the bio-filter. Replace mechanical only; never disturb biological media.
Test ammonia + nitrite + nitrate weekly. By the time fish show symptoms, it is often too late.
"They will work it out" - they will not. Always verify temperament + adult size + water-chemistry overlap.
Excess food rots, spikes ammonia, fuels algae. Feed only what fish eat in 1-2 minutes.
Stuck-on heaters cook tanks. Always pair with an external controller (Inkbird, Apex).
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