Artist.

Japanese name & circle name: ハトの水槽 (Hato no Suisou)
Old name: 仮免雑魚 (Karimen Zako) (reading is a best guess)
Old circle name: ハトサプレッサー

See also

• Pixiv account: http://www.pixiv.net/member.php?id=7043383
• Twitter account: http://twitter.com/hatomizu