Octopus Write and Draw Ink 414 Blue Koi Waterproof Ink for Writing and Drawing, Calligraphy Ink, Non-fading Drawing Ink for Fountain Pen, Blue, 50 ml

It’s an excellent ink for what it’s worth!! People who enjoy archival nature to either write or draw this may be your ink!!

This is my favorite ink, hands down. I use it in pilot vanishing point medium, hongdian m2 medium, twsbi 580 1.1mm stub. Waterproof, doesn't bleed through paper (usually maruman mnemosyne). You can write your signature with this ink.

Love the color & dry time. It’s a little wet in a TWSBI Eco Fine Nib, but I’ll try it with different pens to see the best fit. It’s very similar to De Atramentis Document Blue, but I’d choose this for the better color saturation.

Si buscas una tinta impermeable para una pluma estilografica, esta sí funciona. PERO OJO, esta tinta necesita una pluma con un cierre muy bueno para que la tinta no se seca. Tambien es recomendable de limpiar mas a menudo tu pluma con esta tinta.

Quickly became my favorite blue ink

I got the Blue Koi some time ago, looking for some water-proof inks I could use at work. I had some pigment inks before but most often had issues with the flow and dry starts. So far this one performs with flying colours, but only really tried it in a handful of pens. It is a moderately saturated mid-blue with no undertones, and does present decent shading on fp-paper.

This is one of my favorite blue inks. The color is exquisite. It is a "permanent" ink, so be careful, but it does not feather or bleed unreasonably. It writes well. I have a pen dedicated to this ink, and it has not blocked or had any problems.

I wanted a waterproof blue ink and that's what I got. Flows nicely from the pen and once it dries it isn't going anywhere.