At DAISO (a 100-yen shop / one-dollar shop), I found a small collection box (approx. 6 cm x 6 cm x 5 cm height) that can be used as a recording chamber. The same product was also available at an online shop.
Because the acrylic box is too tall, I made it short using an acrylic scoring cutter and tin snips.
To show visual stimuli to the zebrafish larvae, I used 3.5-inch LCD module, which has a VGA connector (D-SUB 15 pins) and thus can be used as an ordinary PC display. You can show the zebrafish larva Youtube, a movie, or whatever you see on your PC display.
The display was set to face a wall of the acrylic box. Not all the microscopes have enough clearance. In Zeiss scopes, the display could be on the wall of the box.
Because we use GCaMP (GFP-based calcium indicator), we need to remove green component in the visual stimulus. For this purpose, Kodak No.32 (a gelatin filter) was put on the LCD. 
The zebrafish larva is embedded in 2% low melting agarose on a cover slip, which is held on a custom-made holder with a paperclip. In this way, the larva is positioned in the chamber. How the larva is oriented should be determined by the receptive field of the neurons that you are recording from. In the position shown below, the larva sees stimuli through its right eye and the posterior part of the left tectum will respond to the visual stimulus presented on the display. Note that the retinal ganglion cells in the right retina project to the left tectum.
The holder was made by cutting out of a tip box.
A stand for the 3.5-inch display can be made by cutting a tip box into half. Use of acrylic may be much better to build a strong stand.
Web resources
- Collection case DM10 (Yorozu-ya Marché, rakuten.com, Japan)
- 3.5-inch VGA color TFT LCD module CR035DVX2801 (TFT-LCD Kit. Crystage, Japan)
- Kodak Wratten filter No.32. #8494544 Magenta (Minus-green) 75 mm squrare.
