Privacy Policy
Effective October 25, 2026
The short version: only teachers sign in. We store a teacher's email and the classroom data the teacher types in: a first name or nickname for each student's fish, which fish and color they picked, and how many times each fish was fed. We use it only to run Class Fish Tank. We never sell it, never show ads, and never use it to track or profile anyone. Teachers can export or delete it at any time.
Who we are
Class Fish Tank ("we", "us") is a free classroom reward tool run as a personal project. Questions or requests about privacy go to classfishtank@gmail.com.
Who uses Class Fish Tank
Class Fish Tank is for teachers (and other adults running a classroom). Only teachers create accounts and sign in. Students do not create accounts, sign in, or type in any information; they see the tank on the classroom screen. The service is not directed at children for their own use, and we do not knowingly collect personal information directly from children. If you believe a child has created an account, contact us and we will delete it.
What we store
About teachers:
- Email address and password (the password is stored only as a secure hash by our authentication provider). If you sign in with Google, we receive your email address from Google.
- Your classrooms: their names, time zone and settings (fish sizes, swim speed, look, background, decorations).
- Background pictures you choose to upload, kept in a private folder that only your account can read.
- Basic technical records needed to run and secure the service, such as sign-in times and the IP address used to sign in, kept by our providers for a limited time.
About students (entered by the teacher):
- A name for each student's fish. We ask teachers to use first names or nicknames only.
- The fish type and color picked for them.
- How many times their fish was fed today, and the number of feedings per day for the past year (for the leaderboard).
We do not ask for or need student last names, email addresses, birthdays, photos, grades or any other information. Please don't enter them.
How we use it
Only to provide Class Fish Tank to you: to show your classrooms on your devices, keep them in sync, reset the fish each day, show the leaderboard, send account emails (confirming your email, resetting your password) and keep the service secure. We do not:
- sell or rent any information;
- show ads, or use any information for advertising;
- build profiles of teachers or students, or use student information for anything other than your classroom;
- use analytics or tracking cookies in the app.
On the public pages of this website (the home page, Our story, Terms and this page, but not the app), we count visits with Vercel Web Analytics. It uses no cookies, doesn't identify you, and only shows us totals such as how many people visited and which pages they read.
Cookies and storage in your browser
The app keeps your sign-in and a copy of the open classroom in your browser's local storage so it opens quickly and stays signed in. Signing out removes them. We do not use advertising or tracking cookies. The sign-up page uses Cloudflare Turnstile to block automated sign-ups; it may set a cookie needed for that check.
Who else handles the data
We use a few service providers to run Class Fish Tank. They process data only on our behalf and only to provide their service:
- Supabase: database, sign-in and file storage (servers in the United States).
- Vercel: hosting the website.
- Resend: sending account emails.
- Cloudflare Turnstile: the anti-bot check on the sign-in and sign-up forms.
- Google: only if you choose "Continue with Google".
- Ko-fi (with Stripe): only if you choose to leave a tip. You pay on Ko-fi's site; we never see your card details, and tips are not linked to your Class Fish Tank account.
- Tally: only if you send us feedback. The form also tells us the app's language, your screen size and browser type, to help us fix problems. Please don't include student names or photos.
We share information with others only if the law requires it, or to protect the safety of people or the service.
How we protect it
All connections use encryption (HTTPS). Data is encrypted at rest by our database provider. Every request is checked on the server so a teacher can only ever reach their own classrooms, and access to the database is limited. No system is perfectly secure, but if we learn of a breach affecting your information we will tell you without undue delay.
How long we keep it
- Daily feeding records are deleted automatically after one year.
- Everything else is kept until you delete it. Deleting a student, a classroom, or your account removes that data from the live database right away. Backups held by our database provider are overwritten within their backup period.
- We may delete accounts that have not been used for two years, after emailing you first.
Your choices
- See and export: everything is visible in the app; Settings → Fish list exports a CSV file.
- Correct: edit any name or setting in the app.
- Delete: remove a student, a classroom (Settings → Delete this classroom) or your whole account (Settings → Delete my account).
- Or email classfishtank@gmail.com and we will help.
For teachers and schools
Teachers decide what to enter and are responsible for following their school's and district's policies on using online tools with students, including the U.S. Family Educational Rights and Privacy Act (FERPA) and state student privacy laws. We use student information only to provide the service to the teacher, and a parent, guardian or school can ask us (through the teacher, or directly) to review or delete a student's information.
Changes
If we change this policy we will update the date above, and for important changes we will let teachers know by email or in the app before they take effect.