# Fishtank

![Fishtank icon](pwa-192x192.png)

A living aquarium with Freshwater, Bioluminescent, Coral Reef, Jellyfish, Japanese Garden, Amazon Blackwater, Seahorse Garden and Rocky Cichlid categories. The freshwater tank has photographic fish, lush aquascapes, swaying plants, grazing shrimp and a wandering snail. Watch neon tetras school, angelfish glide, guppies flutter their tails and corydoras forage along the sand.

## Tend your tank

Open Fishtank on a shared screen. All active room controllers follow automatically when the aquarium starts. Scan its standard RCWeb QR panel to open [Fishtank Control](/fishtank-c/appinfo) in the same room. Feeding and scenery changes also bring late room controllers into the aquarium without reloading controllers already in Fishtank Control. Click anywhere on the display to toggle full screen.

- Use the tank type selector at the top of Fishtank Control to switch between Freshwater, Bioluminescent, Coral Reef, Jellyfish, Japanese Garden, Amazon Blackwater, Seahorse Garden and Rocky Cichlid. Each category remembers its fish population, scenery, lighting, current and bubbles.
- Add or remove any of six fish species in the selected category, up to 60 fish in total.
- Feed the school and watch fish pursue and eat the sinking food. Servings have an eight-second interval.
- Choose Planted Aquarium, Castle Aquarium or Shipwreck Aquarium scenery, with aquarium gravel, plants and ornaments. The static waterline and outer frame are cropped out, and the residents stay above the gravel surface.
- Scenery cycles every five minutes with a four-second crossfade. Choosing a scene manually restarts the timer.
- Foreground plants shift slightly along the gravel during each scenery crossfade, including return visits, to vary the illuminated pixels on OLED screens.
- Select daylight, golden dusk or moonlight, water flow, and air bubbles.
- Bioluminescent tanks show marine-inspired fish with artistically enhanced neon colors: turquoise, ultraviolet, hot pink, lime, cobalt and amber. Dark bodies, luminous fins and colorful baked bloom create a fantasy light show against Luminous Garden and Violet Grotto scenery. Fish shapes are based on northern lampfish, dusky hatchetfish, black seadevils, twofin flashlightfish, Sloane's viperfish and Australian pineapplefish. See [neon artwork details](neon-artwork.md).
- Hide or show the heading and QR panels independently in the scenery controls.
- Five cherry shrimp and a nerite snail live in freshwater tanks; foreground plants sway in both categories.
- Neon tanks have nine foreground plant clusters: turquoise ribbon grass, violet-pink fern and amber-veined rosettes. Their glow is baked into high-resolution artwork, with gentle current-driven sway and open swimming space above the gravel.
- Coral Reef has clownfish, regal blue tangs, yellow tangs, blue-green chromis, royal grammas and fire gobies. Choose Coral Lagoon or Reef Arch, with white sand, live rock and colourful coral gardens. Seven foreground anemones, sea fans and soft corals sway with the water flow. Reef backgrounds are 3840 × 2160 JPEGs; fish and coral sprites have transparent padding and opaque physical surfaces. See [reef artwork and prompts](reef-artwork.md).

- **Jellyfish:** a near-black exhibit with moon, sea nettle, purple-striped, lagoon, crystal and flower hat jelly artwork. Translucent bells contract, long tentacles flex with a delayed wave, and a gentle current carries the jellies through the water. Choose Midnight Glass or Velvet Dusk; feed drifting plankton and adjust exhibit lighting. The default collection has 12 jellies. See [artwork and generation prompts](/fishtank/jellyfish-artwork.md).

- **Japanese Garden:** twelve koi-inspired fish in six colour varieties, including Kohaku, Sanke, Showa, golden, platinum butterfly and Tancho. Choose Stone Path or Moss Islands, with pale gravel, moss-covered stones, soft daylight, six swaying foreground plants and nine gently drifting maple leaves. Fish, feeding, lighting and scenery use the same shared controls. See [artwork and prompts](/fishtank/garden-artwork.md).

- **Amazon Blackwater:** tea-coloured water, tangled roots and fallen leaves. Root Cathedral and Leaf Lagoon are 4K scenery designs with narrow warm shafts of light. Six fish species include silver dollars, silver hatchetfish, diamond tetras, rummy-nose tetras, black neon tetras and Sterbai corydoras. See [artwork and prompts](/fishtank/amazon-artwork.md).

- **Seahorse Garden:** twelve upright seahorses in golden, peach, ivory, chestnut, sage and rose colour varieties. Curled tails hold onto swaying seagrass stems; the seahorses release, take frequent longer swimming trips in front of and behind the plants, turn beyond the screen edges, hover and settle onto new stems. Choose Seagrass Meadow or Willow Garden, both 4K JPEGs with pearl sand and branching ornaments. Feed small drifting morsels near their snouts. See [artwork and prompts](/fishtank/seahorse-artwork.md).

- **Rocky Cichlid:** eighteen colourful fish in six varieties: electric yellow, cobalt zebra, red zebra, peacock, yellow-tail acei and frontosa. Choose Limestone Caves or Slate Terraces, both 3840 × 2160 JPEGs with pale sand and sculpted rock formations. Individually sized fish patrol local territories, inspect the rocks and retreat behind foreground shelters before emerging again. Four varied caves drift subtly with scenery changes. See [artwork and prompts](/fishtank/cichlid-artwork.md).

One or more visitors can tend the tank together; no player names or accounts are needed. The oldest connected display hosts the tank. Additional displays mirror the fish population and scenery while animating independently. An available display takes over if the host leaves. Tank choices are saved per room in the display browser, when storage is available. Feeding particles are transient.

## Display and graphics

Swimming fish keep their side profile while visible and reverse direction only after their whole body and fins pass beyond the left or right edge. They then swim back into view. Cichlids take occasional edge trips between territory and shelter visits; upright seahorses and pulsing jellyfish retain their distinct movement.

Artwork loads on demand: the selected background, fish sheet and any foreground decoration sheet load first. Other collections and scenery load only when selected; previously visited artwork is reused for the life of the page. The current picture remains visible while the next scene loads, then the scenery fades across. Full-resolution display artwork is unchanged. The control app uses compact preview images instead of downloading display-resolution artwork.

Designed for 2560 × 1440 and larger landscape displays, with responsive landscape and portrait layouts. WebGL 1 renders flexible fish meshes, rippling water and gently swaying plants without external libraries. A Canvas 2D fallback supports older devices. Add `&lean=1` to the room URL for reduced resolution and effects, or `&canvas=1` to force the fallback. Performance depends on the display hardware.

The heading and QR panels shift by up to 10 pixels on each axis to reduce static pixels on OLED screens. Their positions change every 30 seconds with a gentle transition; older devices use small discrete shifts.

The bioluminescent category uses near-black aquascapes and bright fish edges with soft glow baked into the PNG artwork. Fish bodies are fully opaque, so fish in front hide fish behind. Both WebGL and Canvas draw each fish once; there are no runtime bloom filters, extra glow passes or glow framebuffers. This provides an HDR-style appearance in the existing SDR renderer, not native HDR output. The new backgrounds are 3840 × 2160 JPEGs assembled from overlapping generated detail sections.

Original graphics were generated using imagegen. Freshwater fish and ecosystem sprites preserve transparent alpha. Each freshwater aquarium background is a 2560 × 1440 JPEG assembled from four overlapping sections generated with additional photographic detail; the canvas renders at the display resolution. This is a visual aquarium simulation, not a biological care model.

![Planted Aquarium](screenshot.jpg)