In　this　paper,　we　further　explore　multimodal　locomotion　via　an　updated　robotic　fish　model　based　on　Esox　lucius.　Besides　the　improved　actuation　properties　like　higher　torque　servomotors　and　powerful　electronics,　the　robotic　fish　has　some　innovative　mechanical　design　to　pursue　diverse　swimming　modes　and　superior　performance.　Specifically,　we　introduced　a　+/-　50　degrees.　yawing　head　joint　that　functions　as　the　neck　for　enhancing　turning　ability.　A　pair　of　pectoral　mechanisms　with　two　DOFs　per　fin　is　constructed　to　achieve　3-D　swimming　and　to　enrich　multiple　pectoral　motions.　At　the　control　level,　an　improved　central　pattern　generator　(CPG)　model　allowing　for　free　adjustment　of　the　phase　relationship　among　outputs　is　employed　to　produce　rhythmic　signals　of　multimodal　swimming.　Extensive　experiments　were　carried　out　to　examine　how　characteristic　parameters　in　CPGs　including　amplitude,　frequency,　and　phase　lag　affect　the　swimming　performance.　As　a　result,　the　robotic　fish　successfully　performed　various　locomotion　actions　such　as　forward　swimming,　backward　swimming,　turning,　diving,　surfacing,　as　well　as　three　pectoral　motions　in　the　form　of　pitching,　heaving,　and　heaving-pitching.　We　found　that　small　phase　lag　between　oscillating　joints　which　means　large　propulsive　body　wave　length　and　undulation　width　could　lead　to　a　faster　swimming　in　body　and/or　caudal　fin　(BCF)　locomotion.