Kevin — Editor & Site Owner

Cycling means growing a colony of beneficial bacteria that converts toxic ammonia (from fish waste) into nitrite, then into far less toxic nitrate. With the fishless ammonia method a typical 60-100L tank cycles in 4-6 weeks. You're done when both ammonia AND nitrite read 0 ppm within 24 hours of dosing ammonia. Adding fish before this is the single most common reason new fish die in their first month.

Proper acclimation is the difference between healthy new fish and dead ones in 48 hours. The process: float the sealed bag 20-30 minutes to match temperature, drip-acclimate over 30-60 minutes to match water chemistry, then net fish (NEVER pour the bag water) into the tank. Total time: about an hour. Skip it and even hardy species can die from osmotic shock; do it properly and even sensitive shrimp transition without losses.

Some of the most colourful, characterful fish in the hobby stay under 5 cm and thrive in nano tanks. Chili rasboras, celestial pearl danios, ember tetras, and pygmy corydoras are the standouts — all peaceful, all stunning, all suitable for tanks from 20 L upward. The single biggest rule for nano keeping: understocking always beats overstocking, because small water volumes punish mistakes faster than large ones.

Setting up a tropical fish tank takes about £200-£400 for a quality 100 L beginner setup, plus 4-6 weeks of patience for the nitrogen cycle. Skip neither the equipment quality nor the cycling time and your fish will thrive for years. This guide walks the whole thing end-to-end: what to buy, where to put it, how to cycle, and how to stock without killing fish.

Your filter is not a debris catcher — it's a living biological reactor that converts toxic fish waste into something safe. Biological filtration is the only one of the three filter functions that's truly non-negotiable. Pick a filter rated 1.5× your tank volume, never replace all media at once, and never rinse media under tap water. Get those three things right and the filter will keep your fish alive for a decade.

Angelfish (Pterophyllum scalare) suit large community tanks (200L+) with peaceful tank mates that don't fin-nip or get eaten. Best matches: corydoras, bristlenose pleco, larger tetras, peaceful gouramis, kuhli loaches. Avoid: neon tetras (eaten as adults), tiger barbs (fin-nip), bettas (fight).

Aquarium algae has 4 root causes: too much light, too many nutrients, not enough plants, no clean-up crew. Fix the cause + add the right algae eaters (amano shrimp, otocinclus, bristlenose pleco, nerite snails) and the tank stays clean for months.

100 L (25 gallon) opens up real community options — multiple schools, dwarf cichlids as centrepieces, full bottom-dweller groups. Examples for community, biotope, planted, and breeding setups.

A 30 litre tank is small but viable. The honest list: chili rasboras, ember tetras, endlers, sparkling gouramis, single bettas, cherry shrimp, snails, scarlet badis. Avoid: anything that grows over 4 cm or schools of 6+ unless they are nano-shoaling species.

60 L (16 gallon) is the sweet-spot beginner size. You can keep a proper neon tetra shoal, a small group of corydoras, or a mixed community of 15-20 nano fish. The honest list with full community examples.

Bettas are individually unpredictable. Some tolerate tank mates; others kill anything that moves. Safer choices: amano shrimp, nerite snails, kuhli loaches, corydoras (peaceful species). Avoid: guppies, fancy goldfish, other bettas, fin-nippers like tiger barbs.

Fin rot is a bacterial or fungal infection of fish fins, common in bettas and goldfish. Identified by ragged, fraying, blackened, or shrinking fin edges. Treatment: clean water + antibacterial medication (Esha 2000) or aquarium salt for hardy species. Most cases cure in 7-14 days.

Fish swimming sideways usually means swim bladder disorder. Most common in fancy goldfish, bettas, and balloon mollies. Causes: overfeeding, constipation, internal infection, or genetic body shape. Often treatable with fasting + peas + Epsom salt; sometimes terminal.

White spot (ich) is the most common tropical fish disease. It's curable in 7-14 days using a combination of raised temperature (28-30 °C) plus an ich medication or aquarium salt. Catch it early and 95% of fish recover.

Most tropical tanks should sit at 24–26 °C (75–79 °F). Discus and a few specialist species need warmer; some shrimp and white cloud minnows tolerate cooler. This guide covers exact ranges per species, how to pick a heater, and the most common UK temperature mistakes.

Most UK tap water sits between pH 7.2 and 8.0 — fine for the majority of community tropical fish without any adjustment. Only specialist species (discus, wild bettas, blackwater tetras) need soft acidic water; only Lake Malawi cichlids need it harder. This guide covers safe pH ranges per species and the right way to adjust.