Look for "Neuromins", that's the brand name of one algae DHA.
I'm probably going to go for the Thorne DHA (example
here) from one of my typical suppliers. It has the largest dose of DHA per pill (250mg) that I've been able to find so far...as I'm going to shoot for 1 gram of DHA total off the bat (the low end of the DHA supplementation that's been shown beneficial in the studies I've looked at so far).