Aquarium Care Guides
3047 articles- Aquarium Lighting BasicsHow to set photoperiod and intensity for planted tanks, why a timer helps, and how excess light leads to algae.
- Aquarium Heating and TemperatureHow to size an aquarium heater, why a thermometer matters, and safe practices for stable tropical temperatures.
- Aquarium Filtration BasicsThe three roles of filtration (mechanical, biological, chemical), the common filter types, and how to choose a filter by turnover rate.
- Choosing Aquarium Size and LocationWhy larger aquariums are more stable, how much a filled tank weighs, and how to choose a safe, well-supported location away from sunlight an
- Setting Up Your First AquariumA step-by-step approach to a first freshwater aquarium: planning, assembling equipment, rinsing and filling, and cycling the tank before add
- Using Fish Medications SafelyHow to use fish medications safely: read active ingredients, protect the biofilter and invertebrates, remove activated carbon, dose correctl
- External Parasites of FishExternal parasites of fish — monogenean flukes, fish lice (Argulus), and anchor worm (Lernaea): how to recognise them and the generic treatm
- Internal Parasites and DewormingInternal parasites of fish — flagellates, nematodes, and cestodes: recognising white feces and wasting, and the generic medications used to
- Marine Ich (Cryptocaryon irritans)Marine white spot disease caused by Cryptocaryon irritans: its multi-stage lifecycle, and copper, hyposalinity, and tank-transfer treatments
- Treating White Spot Disease (Ich)How to treat freshwater white spot disease caused by Ichthyophthirius multifiliis: the lifecycle, why only the free-swimming stage is treata
- Using Aquarium SaltTherapeutic use of salt (NaCl) in freshwater fish: parasite control, osmoregulatory support, and nitrite (brown blood) protection, plus dosi
- Setting Up a Hospital TankHow to set up a treatment tank: a separate, simple system where sick fish can be medicated without harming the display biofilter or sensitiv
- Diagnosing Sick Fish: A Symptom-Based ApproachHow to investigate sick fish: test water quality first, read clinical signs, and follow a systematic decision path before reaching for medic
- Hydra in AquariumsHydra are tiny freshwater predators with stinging tentacles. They thrive on overfeeding and threaten fry and shrimp; control by cutting feed
- Planaria in AquariumsPlanaria are flatworms that thrive on excess food and detritus. They can prey on shrimp eggs and weak fry and are removed by cutting feeding
- Controlling Pest Snails in AquariumsBladder, ramshorn and Malaysian trumpet snails multiply rapidly when overfed. Populations are reduced by feeding less, trapping, manual remo
- Hair and Thread Algae in AquariumsHair and thread algae form long green strands driven by excess light or a nutrient imbalance. They are controlled by manual removal, rebalan
- Brown Algae (Diatoms) in AquariumsBrown algae are diatoms, single-celled algae with silica cell walls. They bloom in new tanks fed by silicate and usually fade as the system
- Green Water (Algae Bloom) in AquariumsGreen water is a bloom of free-floating algae caused by excess nutrients and light. It is cleared with a blackout, a UV sterilizer or a diat
- Cyanobacteria (Blue-Green Algae) in AquariumsCyanobacteria are photosynthetic bacteria, not true algae. They form slimy mats in low-flow, nutrient-rich tanks and are removed by manual c
- Black Beard Algae (BBA): Causes and TreatmentBlack beard algae is a red alga of the genus Audouinella. It is linked to fluctuating CO2 and organic waste, and can be removed by spot trea
- Aquarium Algae: Causes and ControlAquarium algae grow when light and dissolved nutrients fall out of balance. This guide covers the main triggers and a practical control stra
- New Tank SyndromeWhy uncycled tanks spike ammonia and nitrite, the warning signs in fish, and how to manage and prevent it during the first weeks.
- Controlling Aquarium NitrateWhere nitrate comes from, what levels are considered safe, and the main ways to reduce it: water changes, live plants and denitrification.
- Ammonia Poisoning in AquariumsCauses and symptoms of ammonia poisoning, how pH and temperature change its toxicity, immediate response, and how to prevent it.
- Understanding and Managing pHWhat pH is, what drives it in an aquarium, how carbonate hardness buffers it, the danger of a pH crash, and how to adjust pH safely.
- Water Hardness: GH and KHThe difference between general hardness (GH) and carbonate hardness (KH), how they affect fish and plants, units, and how to raise or lower
- Key Aquarium Water ParametersAn overview of the core water parameters to monitor: temperature, pH, ammonia, nitrite, nitrate, GH and KH, with target ranges and testing.
- Aquarium Water ChangesWhy partial water changes matter, how much and how often to change, dechlorination, temperature matching, and gravel vacuuming.
- Fishless CyclingA method to establish the biofilter by dosing ammonia instead of using fish, with testing milestones and ways to speed it up by seeding medi
- The Aquarium Nitrogen CycleHow beneficial bacteria convert toxic ammonia to nitrite and then nitrate, and why establishing this cycle matters before stocking fish.
- Excess Slime Coat and Grey, Cloudy Skin on Fish: CausesWhy fish turn grey or slimy: water irritants such as low pH, ammonia or chlorine, and ectoparasites such as Ichthyobodo and Chilodonella, wi
- Red, Inflamed or Swollen Gills in Fish: Causes and TestsWhat gill colour and breathing rate reveal: chlorine, ammonia and nitrite injury, gill flukes and bacterial gill disease, the test that conf
- Foam or Bubbles on the Aquarium Surface: What They MeanHow to tell a bubble nest, organic foam, gas supersaturation micro-bubbles and detergent residue apart, what each says about water quality a
- Discus Tank Mates: Temperature, Feeding and Disease RiskDiscus need warm, soft water, at least 26 °C, which rules out many tropical fish. Companions must be calm at feeding time, too big to eat, a
- Angelfish Tank Mates: What to Keep and What to AvoidAngelfish eat fish small enough to fit in their mouths, including neon tetras, and their long fins attract fin-nippers. They need a tall tan
- Snails and Fish: Which Combinations WorkLoaches, pufferfish and some cichlids eat snails, and assassin snails hunt other snails. Nerites suit planted tanks; apple snails eat plants
- Why Aquarium Water Smells Bad: Rotten-Egg, Musty and Fishy OdoursA rotten-egg smell signals hydrogen sulfide from oxygen-free pockets and is an emergency; musty odours come from microbes; a strong fishy or
- pH Keeps Dropping: Causes of a pH Crash and How to Stabilise ItAquarium pH falls when acids from nitrification, decaying organics, wood or leaves and CO2 use up the alkalinity (KH) buffer. Restore it gra
- Cycling Stalled: Why Ammonia or Nitrite Will Not DropA cycle stalls when nitrifying bacteria are starved of alkalinity, kept too cool, poisoned by chlorine or treatments, or overloaded. Test ea
- Carp Edema Virus and Koi Sleepy DiseaseKoi sleepy disease is a gill infection of koi and common carp caused by carp edema virus, a poxvirus. Fish lie listless on the bottom with s
- Goldfish Herpesvirus (CyHV-2): Herpesviral Haematopoietic NecrosisCyHV-2 causes herpesviral haematopoietic necrosis, a highly lethal disease of goldfish. Healthy-looking carriers are common in the trade, an
- Carp Pox in Koi and Carp (Cyprinid Herpesvirus 1)Carp pox is a wax-like skin growth on koi and common carp caused by cyprinid herpesvirus 1. It appears in cool water, usually fades as water
- Keeping Dwarf Shrimp with Fish: Predation, Companions and CoverHow fish size and mouth decide whether adult dwarf shrimp and shrimplets survive, which fish groups sources pair with Neocaridina and Caridi
- Goldfish Tank Mates: Temperature, Size and Coldwater CompanionsWhy goldfish clash with tropical fish on temperature, how adult size and mouth fit endanger small fish, why fancy and single-tailed forms di
- Betta Tank Mates: What Sources Report as Suitable or RiskyWhich fish, shrimp and set-ups are reported as workable or risky with Betta splendens, where water parameters overlap, and the behaviour tha
- Fish Dying One at a Time: A Checklist for Chronic LossesA systematic checklist for slow, repeated fish deaths: water quality trends, stocking and aggression, hidden toxins, chronic infections such
- New Fish Dying in the First Days: Causes and PreventionWhy newly bought fish die within days: transport stress, ammonia and pH shifts in the bag, acclimation mistakes, latent disease and mismatch
- Fish Dying After a Water Change: Causes and What to TestWhy fish die after a water change: chlorine or chloramine, temperature and pH swings, old tank syndrome reversal and dirty buckets, with the
- Eye Fluke (Diplostomum) and Cataracts in FishDiplostomum larvae enter the lens of a fish's eye and cause cataract and blindness. The fluke cycles through snails and gulls, cannot be cur