The First 30 Days: A Simple Maintenance Plan for New Tanks
1) Days 1–7: Stabilize, Test, and Light Feeding
Start with stability. Keep hands out of the tank except for essentials. Run your lights for a conservative 6–7 hour photoperiod while biology matures. Feed lightly—small fish can skip days. Test ammonia and nitrite daily; nitrate every few days. Write numbers in a notebook or app so you spot trends rather than chasing single readings.
Water changes and vacuuming. Perform 20–30% water changes mid‑week if ammonia/nitrite appear, or 10–20% even if they don’t—fresh water resets trace elements and removes dissolved organics. In sand, skim the surface; in gravel, plunge the vacuum gently in a grid. Rinse filter sponges in removed tank water, never under the tap.
Algae prevention beats cure. In week 1, diatoms (brown dust) often appear on glass and leaves; wipe them with a soft pad and keep nutrients modest. Avoid long light hours and bright window glare. Floaters or fast stems help soak up early nutrients. Resist chemical “algae killers”—they often harm beneficial bacteria or sensitive fish.
New‑tank quirk: microbubbles and cloudiness. A slight haze is common as heterotrophic bacteria bloom; it clears as filters catch up. Microbubbles from new tubing or flutes will settle. If the water smells foul (rotten egg), check for stagnant areas in deep sand or soil and increase flow.
2) Days 8–14: Filter Care, Algae Control, and First Trim
Filter care without breaking the cycle. By days 8–14, your mechanical media will have trapped a surprising amount of fine waste. Rinse sponges/floss in a bucket of removed tank water until the brown slurry runs lighter; do not replace all media at once. Ensure impellers spin freely and the filter primes instantly after reassembly—air trapped in canisters can stall flow and heat the motor.
First plant trim. Fast stems grown in emersed farms often shed their old leaves and push fresh submerged growth. Trim ratty leaves, replant healthy tops, and avoid uprooting large sections at once (you’ll release mulm). For rhizome plants (Anubias/Buce), remove algae‑dusted leaves to encourage clean new growth.
Early algae strategy. If green dust algae appears, allow it to grow for a full week, then wipe off and change water—it often breaks the cycle; constant scraping makes it worse. Green spot algae on slow leaves signals low phosphate—dose a balanced fertilizer. Hair algae signals excess light or unstable CO₂; shorten the photoperiod and increase gentle surface movement at night.
Livestock check‑in. Confirm that schooling fish actually school, that bottom dwellers’ barbels are intact (no sharp gravel), and that appetites are normal. Any clamped fins, flashing, or white dots should trigger QT and targeted treatment.
3) Days 15–21: Water Change Rhythm & Stocking Wave #2
Establish your water‑change rhythm. Pick a repeatable day and time (e.g., Sunday morning). Do 30–40% weekly for most community tanks; planted, lightly stocked systems can drop to 20–30%. Consistency matters more than perfection. Keep a “maintenance crate” with conditioner, test kit, towels, aquascaping tweezers, and a spare impeller gasket.
Stocking wave #2. If parameters have been steady and ammonia/nitrite are zero, you can add the next group of fish now. Match species to the bio‑load you can sustain: for a 20‑gallon, adding 6–8 small rasboras or tetras is reasonable. After introduction, test daily for three days and feed lightly.
Equipment audits. Verify heater calibration (a separate thermometer is essential), confirm your filter flow (a dirty pre‑filter or twisted hose can halve it), and re‑level the stand if the floor settled. Noise that wasn’t there on day 1 often points to air caught in a canister or a worn rubber foot under the stand.
4) Days 22–30: Dial‑In Settings and Long‑Term Habits
Dial in your long‑term routine. At the 3–4 week mark, your tank should look clearer and fish behavior should be predictable. Increase photoperiod slowly (30 minutes per week) toward your target if plants need more light. Decide on a fertilizer plan (all‑in‑one vs. macros + micros) and keep notes. Replace worn suction cups and reorganize cables with labeled ties to maintain safe drip loops.
Preventive care checklist. (1) Clean the pre‑filter weekly; (2) rotate gravel‑vac sections so you don’t disturb the whole bed at once; (3) wipe lids and light fixtures to reduce mineral crust; (4) inspect hoses and bulkheads for creep and re‑tighten gently; (5) keep a spare heater and air pump on hand.
Document & photograph. Take full‑tank shots under the same settings each week. This helps you catch slow algae trends, plant nutrition issues (pale new leaves vs. old leaves), and slow growth in fish that indicates underfeeding or parasites. Your notes become the best “owner’s manual” for your unique water.
FAQ
How often should I change water in the first month?
Plan for 20–40% weekly, with extra changes whenever ammonia or nitrite show. Stability and consistency beat perfect numbers.
Do I clean the filter right away?
Rinse only the mechanical stage in tank water around week two. Leave bio media undisturbed. Never clean everything at once.
My water turned cloudy—did I do something wrong?
Likely a harmless bacterial bloom. Keep filters clean, avoid overfeeding, and it will clear as the system balances.
Next reads: Weekly Maintenance Checklist • Water Changes & Gravel Vacuum • Essential Aquarium Equipment