Drop in your tank dimensions, water type, and the fish you want — get back compatibility checks, a real bioload calculation, and substitutions for anything that won't work.
$3.99
Works in Claude (Pro/Max/Team) or ChatGPT (Plus/Team) · paid AI plan required
✓Both Claude + ChatGPT packages included — you can't pick the wrong one.
Updated
Included
01Flags fin-nippers, predator-prey size mismatches, and territory conflicts in your specific list
02Runs bioload math the way it actually works — by adult size and metabolism, not '1 inch per gallon'
03Suggests concrete swaps for incompatibilities: not just 'no', but 'try bristlenose pleco instead of common pleco'
04Covers 80+ freshwater and 40+ saltwater/reef species with temperament, schooling minimums, and parameters baked in
05Renders a printable HTML stocking card you can screenshot and bring to the LFS
You've put $500 into a 55-gallon and you're standing in the fish store about to make a $200 mistake. This aquarium stocking calculator is the conversation AqAdvisor was supposed to be — give it your tank size (gallons and dimensions, because a 55 tall holds fewer cichlids than a 55 breeder), water type, and the species you want, and it returns a fish compatibility checker verdict for every pairing plus a bioload calculation against actual filter capacity.
Three bundled databases do the work: freshwater-species-database.md covers 80+ species (tetras through Mbuna), saltwater-species-database.md covers 40+ marine and reef fish with reef-safety ratings, and bioload-and-tank-guide.md replaces the misleading inch-per-gallon rule with a real unit system that weights fish by adult size, metabolism, and waste. When something won't work — tiger barbs with a betta, mandarin dragonet in a 20-gallon nano reef, common pleco in anything under 150 gallons — it tells you why and offers specific alternatives that fit your parameters.
Built for the moment before you buy: planning a first community tank, settling an argument with the LFS, or rescuing an impulse purchase. Output is a printable HTML stocking card with color-coded compatibility rows and a bioload bar.
Frequently asked
How do I figure out if my aquarium is overstocked before the ammonia spikes?
Paste in your tank size (with dimensions if you have them), filtration setup, and current or planned stock list. The skill runs a bioload calculation that weights fish by adult size and metabolism, factors in your filter type, and reports a percentage capacity used. Under 80% is comfortable; over 90% is a refusal.
Can I check fish compatibility for a saltwater or reef tank, not just freshwater?
Yes. The saltwater database covers 40+ species across clownfish, tangs, wrasses, gobies, angels, and common inverts — with reef-safety ratings, minimum tank sizes (yellow tang = 75g, blue tang = 100g, no exceptions), and known incompatibilities like mandarin dragonets in nano reefs.
Why not just Google the fish I want to add?
Forum threads contradict each other and AqAdvisor's data hasn't been updated in years. This skill has bundled species records with bioload units, schooling minimums, aggression notes, and footprint requirements — grounded in current hobby consensus and explained in one consolidated stocking plan rather than 12 open browser tabs.
Does it understand non-standard setups like African cichlid tanks or species-only nanos?
Yes. It handles Mbuna cichlid tanks (with overcrowding-as-aggression-management logic), nano reefs, planted community, brackish, and species-only setups. Tell it the water type and parameters and the compatibility logic adjusts.
Will it actually push back if I want something stupid, or just rubber-stamp my list?
It pushes back. Goldfish in a tropical community, common pleco in a 55g, two male bettas, oscar in a 40g — all hard refusals with reasons, plus alternative plans. The skill's job is keeping fish alive, not validating bad calls.
Install — no Terminal required
After checkout you land on a page with a one-click download and a pre-built install prompt. Pick the AI you already pay for — both packages are included, so you can't pick wrong.
What you'll see the second your payment clears
Your license key
ST-XXXX-XXXX-XXXX · permanent
Pre-built install prompt⧉ Copy
ChatGPT package (ZIP)⬇ Download
No setup work before you buy — copy, paste, done.
Have Claude Pro, Max, or Team?
Copy the prompt, paste into Claude
Copy the pre-built install prompt from the success page, paste it into any Claude Code chat, and Claude installs the skill itself — about 10 seconds. Using the app instead? Drop the downloaded folder into a Claude Project's knowledge and ask Claude to use it.
Have ChatGPT Plus or Team?
Build a Custom GPT — ~2 minutes
Click Download ChatGPT package (included with every purchase).
Unzip it — inside is a SETUP.md and a knowledge/ folder.
Go to chatgpt.com → your profile → My GPTs → Create a GPT → Configure.
Paste the Name, Description, and Instructions from SETUP.md into the matching fields.
Under Knowledge, upload every file in the knowledge/ folder.
Click Create/Save, open your GPT, and describe your task in plain English.
A paid plan on either platform is required — Claude (Pro, Max, or Team) or ChatGPT (Plus or Team). Comfortable with Terminal? A one-line npx skilltree-network install path is available too.